KR20170060293A - Digital breast tomosynthesis - Google Patents

Digital breast tomosynthesis Download PDF

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KR20170060293A
KR20170060293A KR1020150164520A KR20150164520A KR20170060293A KR 20170060293 A KR20170060293 A KR 20170060293A KR 1020150164520 A KR1020150164520 A KR 1020150164520A KR 20150164520 A KR20150164520 A KR 20150164520A KR 20170060293 A KR20170060293 A KR 20170060293A
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ray
generator
focus
ray focus
trigger signal
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KR1020150164520A
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Korean (ko)
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KR101787714B1 (en
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노영섭
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메디퓨처(주)
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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
    • A61B6/50—Clinical applications
    • A61B6/502—Clinical applications involving diagnosis of breast, i.e. mammography
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
    • A61B6/02—Devices for diagnosis sequentially in different planes; Stereoscopic radiation diagnosis
    • A61B6/03—Computerised tomographs
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
    • A61B6/04—Positioning of patients; Tiltable beds or the like
    • A61B6/0492—Positioning of patients; Tiltable beds or the like using markers or indicia for aiding patient positioning
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
    • A61B6/40—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment with arrangements for generating radiation specially adapted for radiation diagnosis
    • A61B6/4021—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment with arrangements for generating radiation specially adapted for radiation diagnosis involving movement of the focal spot
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
    • A61B6/44—Constructional features of apparatus for radiation diagnosis
    • A61B6/4429—Constructional features of apparatus for radiation diagnosis related to the mounting of source units and detector units
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
    • A61B6/54—Control of apparatus or devices for radiation diagnosis
    • A61B6/547—Control of apparatus or devices for radiation diagnosis involving tracking of position of the device or parts of the device

Abstract

A digital mammographic tomographic image synthesizer according to the present invention includes an X-ray generator for generating an X-ray, an X-ray generator for generating a projection image by converting an X- Ray generator, a trigger signal generator for generating a position signal of the X-ray focus according to the rotation of the X-ray generator, and a position angle detector for detecting the position angle of the X-ray focus corresponding to the position of the X- When the position signal is generated by the trigger signal generator, the position angle of the X-ray focus corresponding to the position signal is read from the storage unit, and the position angle of the read X- The projection image is determined by the position angle of the photographed X-ray focus. According to this, since it is possible to determine an accurate position angle of the X-ray focus without adding a complicated and expensive configuration, it is possible to obtain a high-quality reliable projection image.

Description

[0001] DIGITAL BREAST TOMOSYNTHESIS [0002]

The present invention relates to a digital mammographic tomographic image synthesizer, and more particularly, to a digital mammographic tomographic image synthesizer capable of accurately and easily acquiring a position angle of an X-ray focus at a time of acquiring a projection image.

Cancer that develops due to infinite proliferation of cells includes liver cancer, colon cancer, stomach cancer, and lung cancer. Breast cancer that is especially a female disease is a very fatal disease and needs periodic diagnosis and management. Westernized eating habits are raising the incidence of breast cancer in Asia. Therefore, in each country, it is recommended that women with a certain age or older be diagnosed with breast cancer at regular intervals.

Breast ultrasound (Breast Ultrasonography) and Breast MRI (Breast MRI) are examples of diagnostic methods for breast cancer. Mammography using X-ray is typically used. Mammography obtains an X-ray image of the breast from the image receptor after exposing an appropriate amount of X-rays to the Automatic Exposure Control (AEC).

X-ray image acquisition of the breast is generally performed by FFDM (Full Field Digital Mammography), DBT (Digital Breast Tomosynthesis), and BCT (Breast Computed Tomography). The FFDM acquires a 2D image, and the DBT reconstructs the image using the acquired image while the X-ray generator rotates. The BCT rotates the X-ray generator and the X-ray detector to form a three-dimensional image.

Particularly, in order to obtain a projection image, the DBT for obtaining a 3D image rotates the focal spot of the X-ray about the breast, and the locus of the focus of the X- That is, the patient's chest wall). However, commercially available digital mammographic tomographic image synthesizers tend to be designed to ignore the trajectory of the X-ray focus, even though it should be traveling straight in the horizontal plane.

When a projection image is obtained without designing the rotation accuracy of the rotation axis of the digital breast tomographic image synthesizer, the X-ray focus position of each projection image is not aligned on the horizontal plane with the chest wall of the breast. That is, unlike the desired straight line trajectory of the X-ray focus, the trajectory of the actual X-ray focus is not horizontal to the chest wall, but has an uneven trajectory depending on the position of the X-ray focus. If 3D reconstruction is performed using the projection image obtained in this state, the quality of the 3D image is inevitably poor. That is, when reconstructing an image using a projection image, it is difficult to obtain a proper 3D image because an image reconstruction algorithm is performed while assuming that the trajectory of the X-ray focus moves in a straight line.

In order to reconstruct the image, it is necessary to precisely grasp the position angle at which the X-ray focus is located. However, it is difficult to accurately measure the position angle of the X-ray focus . Reliable position Because of the additional components such as a high-precision angle meter for measuring the angle, there is a drawback that the manufacturing cost is increased. If the image reconstruction is performed appropriately with an approximate value rather than an accurate position angle of the X-ray focus, the quality of the 3D image is inevitably poor.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide a high-quality and reliable 3D image acquisition capable of judging an accurate X-ray focus position angle of a projection image without adding a costly and relatively complicated configuration And to provide a digital mammographic tomographic image synthesizer.

According to an aspect of the present invention, there is provided a digital mammography apparatus comprising: an X-ray generator for generating an X-ray; An X-ray detector for generating a projection image by converting the X-ray irradiated by the X-ray generator and passed through the breast into image information; A rotation unit for rotating the X-ray generator; A trigger signal generator for generating a position signal of the X-ray focus according to the rotation of the X-ray generator; And a storage unit for storing the position angle information of the X-ray focus corresponding to the position of the X-ray focus, wherein when the position signal is generated by the trigger signal generator, The position angle of the X-ray focus is read out and the position angle of the read X-ray focus is determined as the position angle of the X-ray focus of the projection image.

The trigger signal generator may include a plurality of photocouplers, wherein the photocoupler includes: a light emitting unit that generates light; And a light receiving unit for converting a change in the amount of light received from the light emitting unit into an electrical signal.

The trigger signal generator generates a position signal by detecting a change in the amount of light that is generated at the moment when the end of the rod portion passes between the light emitting portion and the light receiving portion, can do.

The plurality of photocouplers may be arranged to generate an electrical signal whenever the X-ray generator generates X-rays.

The trigger signal generator is disposed on the rotation axis of the rotation unit, and can generate a position signal in conjunction with the position of the X-ray focus.

The apparatus according to claim 1, further comprising a reference table unit detachably installed between the X-ray generator and the X-ray detector and having a marker for acquiring an image by the X-ray detector, The position angle information stored in the X-ray detector can be detected based on the positional change of the marker displayed on the projection image obtained by the X-ray detector.

The position angle information stored in the storage unit may include at least one of a position change amount of the marker, a distance from the surface of the X-ray detector to the reference table portion, and a distance from the X-ray focus to the surface of the X- Can be detected.

The trigger signal generator may include an encoder connected to a rotation axis of the rotation unit to generate angle position information of the rotation axis; A memory for storing position information of an X-ray focus corresponding to the angular position information; And a CPU for generating position information of the X-ray focus based on the angular position information generated by the encoder.

The trigger signal generator includes: an encoder, connected to a rotation axis of the rotation unit, for generating angle position information of the rotation axis; A memory for storing position information of an X-ray focus corresponding to the angular position information; And a CPU for generating a position signal of the X-ray focus based on the input signal generated by the trigger signal generator.

According to the digital breast tomographic image synthesizer of the present invention having the above-described configuration, the accurate X-ray focus position angle of the projection image can be determined without adding a relatively complicated configuration with a high cost. Therefore, it is possible to acquire high-quality and reliable 3D images.

1 is a perspective view of a digital mammogram image synthesizer according to an embodiment of the present invention.
2 is a view for explaining a trajectory correction method of a digital mammogram image synthesizer according to an embodiment of the present invention.
3 is a view for explaining a position angle detection method of a digital mammogram image synthesizer according to an embodiment of the present invention.
4A and 4B are views for explaining a position angle measurement method of a digital mammogram image synthesizer according to an embodiment of the present invention.
5 is a view for explaining a method of calculating an X-ray focus position angle of a digital mammogram image synthesizer according to an embodiment of the present invention.
6 is a view schematically showing a position point at which a trigger signal generator generates a position signal in the digital mammogram image synthesizer according to the embodiment of the present invention.
7A and 7B are views for explaining the design and operation principle of a trigger signal generator using a photocoupler in a digital mammography apparatus according to an exemplary embodiment of the present invention.
8 shows a schematic circuit structure of a photocoupler.
9 is a diagram for explaining the design and operation principle of a trigger signal generator using an encoder in the digital mammogram image synthesizer according to an embodiment of the present invention.

The present invention will now be described in detail with reference to the accompanying drawings, which show specific embodiments in which the present invention may be practiced. For a specific embodiment shown in the accompanying drawings, those skilled in the art will be described in detail so as to be sufficient for practicing the present invention. Other embodiments than the particular embodiment need not be mutually exclusive but different from each other. It is to be understood that the following detailed description is not to be taken in a limiting sense.

The detailed description of the specific embodiments shown in the accompanying drawings is read in conjunction with the accompanying drawings, which are considered a part of the description of the entire invention. The reference to direction or orientation is for convenience of description only and is not intended to limit the scope of the invention in any way.

Specifically, terms indicating positions such as "lower, upper, horizontal, vertical, upper, lower, upper, lower, upper, lower ", or their derivatives (e.g.," horizontally, Etc.) should be understood with reference to both the drawings and the associated description. In particular, such a peer is merely for convenience of description and does not require that the apparatus of the present invention be constructed or operated in a specific direction.

It should also be understood that the term " attached, attached, connected, connected, interconnected ", or the like, refers to a state in which the individual components are directly or indirectly attached, And it should be understood as a term that encompasses not only a movably attached, connected, fixed state but also a non-movable state.

The thicknesses and sizes of the respective components shown in the accompanying drawings are exaggerated, omitted, or schematically shown for convenience and clarity of explanation. That is, the size of each component does not entirely reflect the actual size.

1 is a perspective view of a digital mammogram generating apparatus 100 according to an exemplary embodiment of the present invention. 1, a digital mammography apparatus 100 according to an exemplary embodiment of the present invention includes an X-ray detector 110, a compression paddle 120, an X-ray generator 130, a gantry 140 A rotary part 150, and a reference table part 160. [

The X-ray detector 110 has a function of converting the X-ray passing through the breast U into image information and can simultaneously perform a function as a bucky for placing the patient's breast U . However, in another embodiment, a separate configuration for accommodating the X-ray detector 110 may be further included.

The X-ray detector 110 may be implemented with various types of detectors such as a screen-film detector, an indirect conversion digital detector, a direct conversion digital detector, and the like. Also, although not shown in FIG. 1, a grid (not shown) for removing scattered X-rays may be provided in the bucky of the X-ray detector 110.

The push paddle 120 is designed to be movable up and down, and may be provided between the X-ray generator 130 and the X-ray detector 110. The pushing paddle 120 is preferably made of a material that does not affect the X-ray image acquisition of the breast U, and the up-and-down movement can be controlled so as not to be damaged by the pressing. For example, when a force exceeding a threshold value is applied to the patient's breast U, the downward movement of the pushing paddle 120 may be stopped or controlled to reduce the urging force. At this time, in order to obtain a clear X-ray image, the breast U needs to be evenly compressed.

The X-ray generator 130 is provided above the X-ray detector 110. Although FIG. 1 shows the X-ray generator 130, in another embodiment, the X-ray generator 130 may be referred to as a C-arm and may be designed to have an X- Do. The X-ray generator 130 includes a high voltage generator (not shown) for supplying energy, an X-ray tube (not shown) for converting energy into X-rays, a collimator And other components necessary for the implementation of a digital mammographic tomographic image synthesizer.

Ray detector 130. The patient's breast U is placed on the upper surface of the X-ray detector 110 and the breast U is compressed by the compression pad 120. The X- The line passes through the compressed breast U and reaches the X-ray detector 110. The X-ray detector 110 generates a signal for the position of the X-ray and the incident amount, and this information can acquire an X-ray image of the breast U by an image reconstruction algorithm. At this time, the position angle with respect to the X-ray focus is used for image processing, and the process of measuring the accurate position angle will be described in detail below. Various conventional methods can be applied to image processing of an X-ray image. Therefore, in order not to obscure the essence of the present invention, a detailed description related to the image processing will be omitted here.

It is preferable that the locus of the X-ray focus due to the rotation of the X-ray generator 130, that is, the locus of the X-ray focus, lies on a straight line in a plane horizontal to the chest wall of the breast U, It is necessary to correct the error of the locus of the vehicle.

1, the gantry 140 includes a rotation unit 150 for rotating the X-ray generator 130. When the rotation unit 150 is operated, the X-ray detector 110, The X-ray generator 120 maintains its position, and only the X-ray generator 130 can be rotated within a predetermined range.

Except for the external (e.g., bucky) of the X-ray detector 110, which optionally supports the push paddle 120 and the breast U and the breast U, the X- The X-ray generator 110 and the X-ray generator 130 may rotate integrally. The rotation of each configuration may be designed to allow selective rotation, or it may be designed to be controlled through conversion of the mode (manual or automatic).

The digital mammography apparatus 100 according to an exemplary embodiment of the present invention further includes a reference table 160 between the X-ray detector 110 and the X-ray generator 130. The reference table portion 160 is spaced a predetermined distance from the surface of the X-ray detector 110. In addition, the reference table portion 160 includes a marker 161 having a predetermined shape (e.g., a cross shape).

The markers 161 generate an image on the X-ray detector 110 while the X-rays irradiated from the X-ray generator 130 pass. Accordingly, the marker 161 can be printed, deposited or inserted into a material having a high specific gravity such as lead (pb).

On the other hand, the region other than the markers 161 of the reference table portion 160 is preferably formed of a material having a high X-ray transmittance. Therefore, when the X-ray passes through the reference table portion 160, only the shape of the marker 161 is detected as an X-ray image by the X-ray detector 110.

At this time, the size of the marker 161 and the height of the reference table portion 160 can be appropriately selected so as to be distinguishable from the projection image acquired by the X-ray detector 110. In addition, the position can be adjusted according to the distance (SID, Source to Image-Receptor Distance) from the X-ray focus to the surface of the X-ray detector 110.

Since the area occupied by the image detected by the X-ray detector 110 becomes too large if the thickness of the marker 161 is too large (for example, when the horizontal line and the vertical line are too thick in the cross-shaped marker 161) It is difficult to find the center point. This results in making it difficult to recognize the moving distance of the image of the marker 161, which will be described later.

Therefore, it is preferable that the thickness of the marker 161 is appropriately thin. But it is not limited thereto. The height of the reference table portion 160 may vary depending on the thickness of the marker 161. The height of the reference table portion 160 may be set to about 10 to 20 pixels in the projection image obtained by the X- The position of the food portion 160 can be selected. However, this is merely an embodiment, and in another embodiment, the height of the reference table portion 160 may be set so that the number of pixels is larger or smaller than the size of the range.

FIG. 2 is a view for explaining a locus correcting operation of an X-ray focus of a digital mammogram image synthesizer 100 according to an embodiment of the present invention. Since the currently available commercial tomographic image synthesizer is designed without considering the rotation accuracy of the rotation axis, the locus of the X-ray focus, that is, the locus of the X-ray focus detected by the X-ray detector, is not straight. In view of the above, the digital mammographic tomographic image synthesizer 100 according to the present invention is configured such that the X-ray focus locus in the X-ray detector 110, which is detected while rotating the X-ray generator 130, , We propose a method that can calibrate to obtain the same effect as making it straight.

That is, the digital breast tomographic image synthesizer 100 according to the present invention does not need software of a complicated algorithm or hardware that causes an increase in cost, so that it is possible to use the markers 161 of the reference table portion 160 only very easily, The error of the locus of the X-ray focus of the image can be corrected.

The ideal X-ray focus trajectory is straight in a direction horizontal to the patient's chest wall, such as the RL shown by the dotted line in FIG. This means that the X-ray generator 130 rotates horizontally without an error in the vertical direction. When the projection image generated by the ideal rotation of the X-ray generator 130 passes through an image reconstruction algorithm, the quality (resolution) of the finally generated 3D image is very good.

In the storage unit (not shown) of the digital breast tomographic image synthesizer 100 according to the present invention, an ideal trajectory of the X-ray focus may be stored. This may be data quantized so as to have a constant y coordinate value with respect to the x coordinate, or image data expressed linearly.

The digital mammography apparatus 100 according to the present invention is capable of detecting an X-ray focal point (numerical data, image date, etc.) stored in a storage unit (not shown) The projection image obtained using the trajectory is corrected to be the projection image obtained by using the ideal X-ray focus trajectory. At this time, the actually detected X-ray focus locus corresponds to the image locus of the marker 161 detected by the X-ray detector 110.

The digital mammogram generating unit 100 generates a digital mammogram based on the locus of the marker 161 displayed on the projection image detected by the X-ray detector 110 in accordance with the rotation of the X-ray generator 130, Thereby correcting the projection image so as to be in the ideal horizontal position. At this time, an error is detected by comparing numerically the stored X-ray locus RL of the storage unit (not shown) and the locus XL of the marker 161 or by comparing deviations on the image.

Specifically, the X-ray locus RL (ideal reference locus) stored in the storage unit (not shown) is located at a predetermined height in the y-axis direction and lies on a straight line in the x-axis direction. The correction value? Y n of the y coordinate for each projection image according to the position of each X-ray focus FS with respect to the locus XL of the marker 161 and the stored X-ray locus RL, Which is a natural number of 1 or more, which means the sequence number of the projection image). The correction value? Y n corresponds to a deviation between the y coordinate value of the locus XL of the marker 161 and the y coordinate value of the stored X-ray locus RL.

In FIG. 2, the locus XL of the marker 161 is shown continuously, but may be substantially discrete, when all the projection images are viewed in succession. In case of a discrete image, points that have not been shot directly may be interpolated to calculate the y-coordinate value, or a straight line connecting the points to find the y-coordinate value of the point. This is only an example, and the trajectory XL of the actual marker 161 can be obtained in various ways.

Even as a concept, such as in 2 for each projection image according to the position of each shot point, that is X- ray focus in accordance with the position of the marker 161 shown in the image correction value of the y coordinate (Δy n, where n is a natural number of 1 or more projection And the correction can be performed by moving all the pixel values of each projection image by a correction value (y n ) of the y coordinate.

As described above, the digital breast tomographic image synthesizer 100 according to the present invention can correct the vertical direction error (corresponding to the y-axis in FIG. 2) due to the rotation of the X-ray generator 130. Since the error in the left-right direction (corresponding to the x-axis in Fig. 2) is corrected by the position angle measurement described later, it is not necessary to perform another correction.

FIG. 3 is a diagram for explaining a position detection method of the digital mammogram image synthesizer 100 according to an embodiment of the present invention. 3, the reference table portion 160 is positioned at a predetermined height from the X-ray detector 110 and the marker 161 printed, deposited or inserted into the reference table portion 160 is transferred to an X- 130 are rotated to form an image on the X-ray detector 110. At this time, the circumferential points (FS) shown in FIG. 3 represent the X-ray focus.

The X-ray generator 130 is rotated about the rotation center A by the rotation unit 150 and the X-ray focus FS is rotated by the rotation of the X- Move in the interval.

Although the center of rotation A is shown as being on the surface of the X-ray detector 130 in FIG. 3, it may alternatively be located at a distance from the X-ray detector 130 a predetermined distance, It can be appropriately adjusted at the time of designing the tomographic image synthesis.

The position angle to be measured in the digital mammographic tomographic image synthesizer 100 according to an embodiment of the present invention is determined by the angle at which the X-ray focus FS is positioned with respect to a line segment perpendicular to the rotation center A angle indicated by?).

The positional shift of the X-ray focus FS causes the movement of the marker 161 in the projection image, and the digital mammogram image synthesizer 100 according to the present invention causes the X-ray detector 110 to detect the marker The position angle alpha of the X-ray focus FS can be calculated according to the positional shift of the X-ray focusing point 161.

4A, when the patient's breast U is pressed between the X-ray detector 110 and the pushing paddle 120, the X-ray generator 130 is rotated by the rotation unit 150 X-rays are generated at the position. The X-ray detector 110 detects the X-ray image of the breast U and the image of the marker 161 in accordance with the movement of the X-ray focus FS. It can be seen that the image of the marker 161 detected by the X-ray detector 110 has shifted from a to a 'as shown in FIG. 4B. The digital mammographic tomographic image synthesizer 100 according to the present invention can detect the position angle alpha of the X-ray focus FS based on the positional change on the image of the marker 161 acquired by the X- .

Although the X-ray image of the crisscross marker 161 is shown as being clearly detected in FIG. 4B, in practice, the X-ray image of the marker 161 may be relatively blurry.

At this time, the distance of the image of the marker 161 can be confirmed in such a manner that the center of the crisscross marker 161 is found based on the brightness and darkness of the detected image, and the moving distance of the center thereof is detected. However, the present invention is not limited to this method, and it is possible to detect the moving distance in various ways without difficulty.

FIG. 5 is a view for explaining a position angle detection method of the digital breast tomographic image synthesizer 100 according to the present invention. Where D is the X-ray focus, A is the rotation center of the X-ray focus, C is the position of the marker 161, B is the center position of the X-ray focus, E is the X- The position of the marker 161 detected by the X-ray detector 110 is indicated. On the other hand, the line segment AD is a distance (SID) from the X-ray focus D to the surface of the X-ray detector 110, and is a predetermined value in designing the digital mammogram image synthesizer. The position of the reference table portion 160 can be determined according to the distance SID to the surface of the X-ray detector 110. For example, when the SID is 65 cm, the position of the reference table portion 160 is determined by the X- Lt; RTI ID = 0.0 > cm. ≪ / RTI > Of course, the present invention is not limited to such distances as mentioned above.

The digital mammographic tomographic image synthesizer 100 according to the present invention can calculate the position angle alpha of the X-ray focus using the following equation.

Figure pat00001

In the above equation, since the line AC (= the height of the marker 161) and the line segment AD (= SID) are predetermined values already known by the user, the position of the marker 161 on the X- By acquiring only the value of the change line segment AE, the position angle alpha of the X-ray focus can be calculated.

The digital breast tomographic image synthesizer 100 according to the present invention adds only the reference table type portion 160 on which the markers 161 are displayed without adding a complicated configuration to measure the accurate position angle of the X- The locus of the X-ray focus can be corrected. It is used to acquire high quality 3D X-ray images.

The reference table portion 160 included in the digital mammographic image synthesizer 100 according to the present invention may be detachably fixed. That is, after the trajectory of the X-ray focus FS is corrected, only the correction value may be stored in a storage unit (not shown), and the stored correction value may be applied to a projection image to be generated in the future. At this time, the reference table portion 160 may be removed from the digital breast tomographic image synthesizer 100.

After all the position angles of the X-ray focus FS are detected, the detected position angles are stored in a storage unit (not shown), and a position angle corresponding to the rotation angle of the X-ray generator 130 is stored (Not shown), and may be used for image reconstruction. That is, the reference table portion 160 used in the digital mammographic tomographic image synthesizer 100 according to the present invention may be detachably mounted so that it can be attached only when necessary, and used for locus correction and position angle measurement of the X-ray focus .

In the above description, the detection of the position angle of the X-ray focus FS using the reference table portion 160 has been described. Hereinafter, the digital mammographic tomographic image synthesizer 100 according to an embodiment of the present invention, which uses the position angle information of the X-ray focus FS stored in a storage unit (not shown), will be described.

When the position of each X-ray focus FS is determined, the digital mammomotor image synthesizer 100 according to an embodiment of the present invention stores the position angle information of the X-ray focus FS corresponding to the position, (Not shown), and determines the read position angle as the position angle of the projection image photographed at the corresponding X-ray focus FS.

At this time, the position angle information of the X-ray focus FS may be detected using the above-described reference table portion 160, or detected through a device such as a high precision goniometer. The position angle information detected in various manners can be stored in the storage unit (not shown) together with the position of the X-ray focus FS.

The digital mammography apparatus 100 according to an exemplary embodiment of the present invention includes a trigger signal generator 200 for generating a position signal related to a position of an X-ray focus FS, that is, .

The trigger signal generator 200 synchronizes with the X-ray focus FS of the X-ray generator 130 to generate a position signal of the X-ray focus FS at a constant position.

The trigger signal generator 200 for generating a position signal of the X-ray focus FS includes a plurality of photocouplers (PC), and a plurality of photocouplers The position signal of the X-ray focus FS can be generated based on the output signal generated by the plurality of photocouplers PC arranged at predetermined intervals.

Alternatively, in the digital mammographic tomographic image synthesizer according to another embodiment of the present invention, the trigger signal generator 200 for generating the position signal of the X-ray focus FS includes an encoder, (Corresponding to the angular position of the rotation axis of the rotation unit 150).

The encoder is connected to the rotation axis of the rotation unit 150 and has a function of displaying the angular position of the rotation axis. The trigger signal generator 200 using the encoder may generate the position signal of the X-ray focus FS by an electrical signal, but may generate the position signal by a software command.

First, a trigger signal generator 200 using a photocoupler (PC) will be described. When the rotation of the X-ray generator 130 is performed by the rotation unit 150, the trigger signal generator 200 generates a position signal corresponding to the position of the X-ray focus FS, and the X- A projection image is generated by a line. Since the position of the X-ray focus FS can be known by the position signal generated by the trigger signal generator 200, the position angle? Of the X-ray focus FS corresponding to the position signal can be detected, (Not shown). As will be described later, the position angle information corresponding to the position of the X-ray focus FS may be stored in advance in the storage unit (not shown).

On the other hand, the trigger signal generator 200 using an encoder generates a position signal based on an encoder output value directly output from an encoder connected (or attached) to the rotation axis of the rotation unit 150.

Since the trigger signal generator 200 is designed to operate in conjunction with the X-ray focus FS whether using a photocoupler or an encoder, the position of the X-ray focus FS generated by the trigger signal generator 200 The information indicates the position of the X-ray focus FS in which the projection image is taken as it is. Since the position angle alpha of the X-ray focus FS corresponding to the position signal is detected and stored in the storage unit (not shown) by the various methods described above, the X- It is not necessary to newly detect the position angle alpha of the position detecting sensor FS every time. That is, the position information of the X-ray focus FS can be acquired by a simple configuration without additional calculation or detection, and the position angle information at that time can be read from the storage unit (not shown) and used.

6 is a view schematically showing a position point GS at which the trigger signal generator 200 generates a position signal in the digital mammomotor image synthesizer 100 according to an embodiment of the present invention.

At this time, the position point GS shown in FIG. 6 can be variously analyzed according to the implementation method of the trigger signal generator 200. For example, in the case of the trigger signal generator 200 using a plurality of photocouplers (PC), the position point GS may correspond to the physical position of the photocoupler PC. Further, in the case of the trigger signal generator 200 using an encoder, the position point GS may correspond to a specific value (angular position of the rotation axis, etc.) of the encoder.

In Fig. 6, the X-ray focus FS is displayed at a predetermined interval on a virtual circumference drawn while the X-ray generator 130 rotates. On the dotted line connecting the X-ray focus FS and the X-ray detector 110, a position point GS at which a position signal is generated is displayed. That is, in terms of the rotation angle, the position angle of the position point GS at which the position signal is generated is the same as the position angle of the X-ray focus FS.

 Since the position signal generated by the trigger signal generator 200 must be matched with the position of the X-ray focus FS in the case of the trigger signal generator 200 using the photocoupler PC, Should be the same as the arrangement of the X-ray focus FS for photographing the projection image. That is, the angle at which the photocouplers PC are spaced apart is equal to the spacing angle between the plurality of X-ray focal points FS.

FIG. 6 is a conceptual diagram for helping understanding the above description. The trigger signal generator 200 may be designed in various other structures as long as it can generate a position signal in conjunction with the X-ray focus FS .

The trigger signal generator 200 can be designed such that the X-ray focus FS and the position point GS are arranged at regular intervals as shown in FIG. However, if necessary, the X-ray focus FS and the position point GS may have an uneven arrangement unlike in Fig. For example, if more X-ray images for the breast U need to be obtained at the center, the arrangement of the X-ray focus FS and the position point GS can be designed more densely at the center will be.

Thus, the position of the X-ray focus FS can be obtained through the position signal generated by the trigger signal generator 200, and the position of the X-ray focus FS corresponding to the position of the X- Since the position angle? Of the X-ray focus FS is previously detected by the various methods described above and stored in the storage unit (not shown), the position angle? You can also find out.

The position angle alpha of the X-ray focus FS previously stored in the storage unit (not shown) may have the form of the table shown in Table 1 below, but it is an example only and may be stored in a different form .

Here, GS n may mean a position point GS located at the very center in FIG. 6, and may correspond to a photocoupler (PC) located at the very center among a plurality of photocouplers (PC) . If an encoder is used, it can be handled when the rotation axis of the rotation unit 150 is rotated to the central position.

Location information ... GS n -2 GS n -1 GS n GS n +1 GS n +2 ... Position angle (α) ... -3 ° -1 ° 0 ° 1 ° 3 ° ...

Taking the table of Table 1 as an example, when the photocoupler (PC) corresponding to the position of GS n +2 generates an electric signal, the trigger signal generator 200 generates a position signal based thereon. At the same time, the X-ray is irradiated at the position of the corresponding X-ray focus FS to generate a projection image. On the other hand, based on the table stored in the storage unit (not shown), 3 ° which is the position angle? Corresponding to GS n + 2 is read out, which is the X-ray focus FS for the projection image generated above. Is used as the position angle?

7A and 7B are diagrams for explaining the design and operation principle of the trigger signal generator 10 using the photo coupler (PC) in the digital mammographic tomogram synthesizer 100 according to the embodiment of the present invention. 8 shows a schematic circuit structure of a photocoupler (PC) used therefor.

7A and 7B, the trigger signal generator 200 may include a rotation unit 150, a rod unit 155, and a plurality of photocouplers (PC). The rod section 155 may extend in the radial direction from the rotation axis of the rotation section 150.

One end of the rod section 155 is connected to the central axis of the rotation section 150. When the rotation section 150 rotates, the other end of the rod section 155 rotates while passing through the area where each photocoupler PC is located .

At this time, the plurality of photocouplers (PC) may be arranged at a predetermined interval on a circumference formed by the rod section 155 rotating around the rotation axis. Specifically, each photocoupler (PC) may have a configuration in which a distance in a line is spaced apart, or a configuration in which the photocouplers (PC) are spaced apart at a predetermined angle.

The position signal generated by the trigger signal generator 200 using a plurality of photocouplers (PC) must be generated in conjunction with the position of the X-ray focus FS. That is, it is preferable that the position signal generated by the trigger signal generator 200 can indicate the exact position of the X-ray focus FS.

7A is a front view of a trigger signal generator 200 including a plurality of photocouplers PC, a rotation unit 150 and a rod unit 155. The other end of the rod unit 155 passes through a circumference shown by a dotted line.

At this time, the other end of the rod portion 155 may take a vertically bent dog shape as shown in Fig. 7B. When the X-ray generator 130 is rotated by the rotation unit 150, the rod unit 155 connected to the rotation unit 150 rotates in conjunction with the rotation, and the other end of the rod- (PC) sequentially, and an electric signal is generated in the photocoupler PC through which the other end of the rod section 155 passes.

At this time, each photocoupler (PC) may include a light emitting portion 12 and a light receiving portion 14 in a 'C' shape as shown in FIG. 7B.

Specifically, as in the circuit diagram shown in Fig. 8, the light emitting portion 12 generates light when power is supplied. To this end, the light emitting portion 12 includes at least one light emitting element.

The light receiving section 14 may include a phototransistor. The emitter of the phototransistor is connected to the ground side, and a predetermined power source (for example, a power source of about 5 V) may be supplied to the collector. The base terminal senses the light generated by the light emitting portion 12, and the magnitude of the current changes according to the amount of light. It becomes possible to determine the position of the X-ray focus FS by using the electric signal corresponding to the magnitude change of the current as the position signal.

Referring to FIG. 7B again, as the rod portion 155 connected to the rotation portion 150 rotates, the other bent end passes between the light emitting portion 12 and the light receiving portion 14.

Since the light generated by the light emitting portion 12 is blocked and is not transmitted to the light receiving portion 14 at the moment when the other bent end of the rod portion 155 is placed between the light emitting portion 12 and the light receiving portion 14, The amount of light sensed by the camera will be rapidly reduced.

The photocoupler (PC) whose amount of received light is drastically reduced generates an electric signal, and the trigger signal generator 200 generates a position signal of the X-ray focus FS based on the electric signal.

The position signal generated by the trigger signal generator 200 indicates that the rotation unit 150 has rotated to the position where the photocoupler PC is positioned and also detects that the X- (Position information) of the position information FS. Since the rotation of the X-ray generator 130 is performed by the rotation of the rotation unit 150, the position of the photocoupler PC generating the position signal can be precisely matched to the position of the X-ray focus FS have.

In another embodiment, the rod portion 155 connected to the rotating portion 150 may be straight. In this case, the photocoupler PC may be arranged such that the linear rod portion 155 passes between the light emitting portion 12 and the light receiving portion 14. When the other end of the straight rod section 155 passes between the light emitting section 12 and the light receiving section 14 as described above, the trigger signal generator 200, based on the signal generated by the photocoupler PC, Lt; / RTI >

9 is a diagram for explaining the design and operation principle of a trigger signal generator using an encoder in the digital mammogram image synthesizer according to an embodiment of the present invention.

The trigger signal generator 200 shown in FIG. 9 includes an encoder 21, a CPU 22, and a memory 23. The encoder 21 may be connected to the rotation unit 150 to generate angular position information of the rotation axis of the rotation unit 150. The encoder 21 may be connected through a means such as a timing belt as shown in FIG. 9, but may be connected directly to the rotation unit 150.

The memory 23 may store position information of the X-ray focus FS corresponding to the angular position of the rotation axis of the rotation unit 150. [ The CPU 22 reads the position information of the X-ray focal point FS corresponding to the angular position information of the rotation axis generated by the encoder 21 from the memory 23. The position information of the X-ray focus FS corresponding to the angular position of the rotation axis may be stored in the memory 23 in advance.

In other words, the trigger signal generator 200 generates specific information corresponding to the position angle of the rotation axis of the encoder 21 as the rotation axis of the rotation unit 150 rotates, and outputs the X-ray focus FS corresponding to the specific information. Is read out from the memory 23 to generate the position signal P FS of the X-ray focus FS.

On the other hand, on the other hand, based on the trigger signal Pi input from the outside (a separately configured trigger signal generator, etc.), the output value of the encoder 21 corresponding to the rotation angle of the rotation section at that time is read, ) May be read.

As described above, the digital mammographic tomographic image synthesizer according to the present invention can detect the position of the X-ray focus through the trigger signal generator 200 using a plurality of photocouplers (PC) or encoders 21, It is not necessary to calculate the position angle? Every time by reading out the position angle? Information corresponding to the position of the detected X-ray focus FS from the storage unit (not shown).

The digital mammographic tomographic image synthesizer 100 according to the present invention can perform an additional calculation process using a simple configuration such as a photocoupler (PC) or an encoder 21 composed of a light emitting portion 12 and a light receiving portion 14 Without the detection process, it becomes possible to find out the accurate position angle [alpha] with respect to the X-ray focus (FS) of the projection image.

The digital breast tomographic image synthesizer 100 according to the present invention has an extremely simple structure such as the trigger signal generator 10 including the light emitting unit 12 and the light receiving unit 14, It is possible to determine an accurate position angle with respect to the focus.

Although the present invention has been described in terms of specific embodiments including the preferred embodiments of the present invention, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, It can be predicted. In addition, various structural and functional modifications can be made without departing from the scope and spirit of the present invention. Accordingly, the spirit and scope of the present invention may be widely understood as set forth in the claims appended hereto.

100 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥
110 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ X
120 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥
130 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ X-
140 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ Gantry
150 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥
155 占 쏙옙 占 쏙옙 占 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥
160 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥
161 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ Markers
PC ‥‥‥‥‥‥‥‥‥‥‥‥ Photo coupler
12 ......... .. .. light emitting portion
14 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥
21 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ Encoder
22 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ CPU
23 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥

Claims (9)

An X-ray generator for generating X-rays;
An X-ray detector for generating a projection image by converting the X-ray irradiated by the X-ray generator and passed through the breast into image information;
A rotation unit for rotating the X-ray generator;
A trigger signal generator for generating a position signal of the X-ray focus according to the rotation of the X-ray generator; And
And a storage unit for storing position angle information of an X-ray focus corresponding to a position of the X-ray focus,
Wherein when the position signal is generated by the trigger signal generator, the position angle of the X-ray focus corresponding to the position signal is read from the storage unit, and the position angle of the read X- And determining the position angle of the line focus. The method according to claim 1,
Wherein the trigger signal generator includes a plurality of photocouplers,
The photo-
A light emitting portion for generating light; And
And a light receiving unit that converts a change in the amount of light received from the light emitting unit into an electrical signal. 3. The method of claim 2,
And a rod portion in the longitudinal direction fixed to the rotating portion,
Wherein the trigger signal generator generates a position signal by sensing a change in an amount of light that is generated when an end of the rod unit passes between the light emitting unit and the light receiving unit. 3. The method of claim 2,
Wherein the plurality of photocouplers are arranged to generate an electrical signal each time the X-ray generator generates X-rays. The method according to claim 1,
Wherein the trigger signal generator is disposed on a rotation axis of the rotation unit and generates a position signal in conjunction with the position of the X-ray focus. The method according to claim 1,
And a reference table unit detachably installed between the X-ray generator and the X-ray detector and having a marker for obtaining an image by the X-ray detector,
Wherein the position angle information stored in the storage unit is detected based on a change in position of the marker displayed on the projection image acquired by the X-ray detector. The method according to claim 6,
The position angle information stored in the storage unit
Ray detector is detected on the basis of a position change amount of the marker, a distance from the surface of the X-ray detector to the reference table portion, and a distance from the X-ray focus to the surface of the X-ray detector. The method according to claim 1,
Wherein the trigger signal generator comprises:
An encoder coupled to a rotation axis of the rotation unit to generate angular position information of the rotation axis;
A memory for storing position information of an X-ray focus corresponding to the angular position information; And
And a CPU for generating position information of the X-ray focus based on the angular position information generated by the encoder. The method according to claim 1,
Wherein the trigger signal generator comprises:
An encoder coupled to a rotation axis of the rotation unit to generate angular position information of the rotation axis;
A memory for storing position information of an X-ray focus corresponding to the angular position information; And
And a CPU for generating a position signal of the X-ray focus based on an external input signal.
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