KR20160117730A - Automatic variable aperture collimator for chest digital tomosynthesis - Google Patents

Abstract

The present invention relates to a variable apparatus for adjusting the irradiation range of a digital tomosynthesis system of a trapezoid shape wherein the side of a direction where an X-ray tube moves is configured to have a trapezoid shape that is longer in length than the side of the opposite direction. The present invention relates to an automatic variable apparatus for adjusting the irradiation range of a chest digital tomosynthesis system and a method for controlling the automatic variable apparatus for adjusting the irradiation range capable of obtaining the necessary information of a patient image without omission and reducing exposure dose of a patient wherein the form of an X-ray to which an apparatus for adjusting an irradiation range of a trapezoid shape is configured to adjust to fit the size of a detector. The present invention relates to a digital tomosynthesis system comprising: an X-ray source for irradiating an X-ray; an apparatus for adjusting an irradiation range that adjusts the shape and size of a flux emitted from the X-ray source; a detector for detecting an X-ray projection image that is projected through the apparatus for adjusting an irradiation range from the X-ray source; and a control apparatus for control the movement of the X-ray source and the detector. In the X-ray irradiation window of the apparatus for adjusting an irradiation range, the side of a direction where an X-ray tube moves is configured to have a trapezoid shape that is longer in length than the side of the opposite direction. The control apparatus is characterized by adjusting the size of an oblique side of the X-ray irradiation window of the apparatus for adjusting the irradiation range so that the form of an X-ray irradiated to a patient fits to the size of a detector.

Description

[0001] The present invention relates to an automatic variable aperture collimator for chest digital tomosynthesis,

The present invention relates to an X-ray irradiation window of a variable irradiation range adjusting apparatus of a digital tomographic image synthesizing system, wherein a variation in a direction in which an X-ray tube moves is a trapezoidal shape The irradiation range regulating device of this trapezoidal shape adjusts the shape of the irradiated X-ray according to the size of the detector, thereby reducing the dose of the patient while obtaining the information necessary for the patient image, And more particularly, to a control method of an automatic variable irradiation range control device and an automatic variable irradiation range control device of a digital tomography image synthesis system for chest radiography.

The digital tomographic image synthesis system for chest radiography constitutes a three-dimensional sectional image at a limited angle. The simple mechanical structure makes it possible to provide a sectional image of a resolution superior to that of a general X-ray image, The digital tomographic image synthesis system for chest radiography is effective for detection of pulmonary nodules and early cancers, which are difficult to diagnose due to overlapping of tissues, because of the disadvantages of tomography (CT) and information of depth direction which is a disadvantage of general radiography .

 Pulmonary nodule is a small spherical lesion with a diameter of less than 3 centimeters in the lung. Usually it does not show any signs of symptoms, so it is usually detected by chest X-ray or CT during physical examination. However, the risk of low X- , A digital tomographic image synthesis system for chest radiography is expected to be the most appropriate imaging technique.

 A collimator is a means of adjusting the shape and size of the beam to prevent unnecessary radiation coming into the patient, reducing the half-shadow and reducing the scattering line to increase the quality of the image. The range of the irradiation range adjusting device includes diaphragm type linear velocity regulator, conical type and cylindrical type regulator, and variable linear velocity regulator. It limits the direction and diffusion of the radiation and irradiates only the necessary direction, It is made of a material that absorbs radiation such as lead or tungsten to be shielded and is attached to the front of the X-ray tube. That is, as shown in FIG. 1, an irradiation range adjusting device 120 is installed in front of the X-ray tube 110 to adjust the irradiation range adjusting device 120 to limit the direction and diffusion of the irradiation. The conventional irradiation range adjusting device 120 is formed of a rectangular or square shape.

Since the chest digital tomographic image synthesis system moves the X-ray tube linearly, X-rays are irradiated at a limited angle such as ± 30 ° and ± 50 °. Therefore, when entering at an angle other than 0 °, An additional dose is irradiated to the part off the detector. The additional dose beyond this detector is useless for patient imaging and serves to increase the patient dose.

Therefore, there is a need for an adjustable irradiation range adjusting device of a digital tomography image synthesizing system which can reduce the dose of patient's exposure while obtaining information necessary for the patient image.

In the prior art, Japanese Laid-Open Patent Application No. 2012-65947 relates to a variable-type radiographic imaging system, a storage container used therein, and a portable radiographic image projection set, And a range-limited sheet. The simple irradiation range limiting sheet is configured to selectively remove the square of a large, medium, and small size formed in the center of the inner side, thereby limiting the direction and diffusion of the irradiation. Therefore, the irradiation range regulating device of Japanese Laid-Open Patent Application No. 2012-65947 is made of a rectangular shape so that an additional dose can be irradiated to the portion deviating from the detector.

SUMMARY OF THE INVENTION A problem to be solved by the present invention is to provide a digital tomographic image synthesizing system which comprises a trapezoidal X-ray irradiation window which is configured to take a trapezoidal shape having a longer length than a side of a direction in which an X- The irradiation range regulating device of this trapezoidal shape adjusts the shape of the irradiated X-ray according to the size of the detector, thereby reducing the dose of the patient while obtaining the information necessary for the patient image. And a control method of the automatic variable irradiation range regulating apparatus of the digital tomography image synthesizing system for chest radiography.

According to an aspect of the present invention, there is provided an X-ray imaging apparatus including an X-ray source for irradiating X-rays, an irradiation range adjusting device for adjusting the shape and size of the beam emitted from the X- A digital tomographic image synthesis system comprising: a detector for detecting a line projection image; and a control device for controlling the movement of the X-ray source and the detector, wherein in the X-ray irradiation window of the irradiation range adjustment device, And a trapezoidal shape having a longer length than the sides in the opposite direction.

The control device adjusts the size of the oblique side of the X-ray irradiation window of the irradiation range adjusting device by adjusting the shape of the X-ray irradiated to the patient to the size of the detector.

The irradiation range adjusting device includes a plate having an X-ray irradiating window for passing X-rays inside, and a collimate blade is provided on each of the upper, lower, left, and right sides of the rim of the X- There are two or more control sticks on one side of the collimator wing.

The control rod is made up of a linear actuator, and the length of each control rod is adjusted so that the collimator wing moves up and down or has a specific angle.

The controller adjusts the irradiation range of the irradiation range adjusting device by obtaining the length of the X-ray irradiation window of the irradiation range adjusting device in order to acquire an image of a predetermined size according to the angle (?) Of the X-ray source.

The control device receives the system operation data including the total rotation angle and the number of projections from the input unit, obtains the rotation angle (?) Of the x-ray source, and adjusts the irradiation range The length of each side of the X-ray irradiation window of the apparatus is obtained, and a control rod control signal is generated in accordance with the length of each side of the X-ray irradiation window and transmitted to the irradiation range control section.

The height (l _y ) of the X-ray irradiation window of the irradiation range regulating device

l _y = l _y1 + l _y2

(Where, l _y1 = (a and d) / (L - b) and, l _y2 = (a and d) / (L + b), and, b = (a L _x and sinθ) / 2, a = L _x / (2cos &_amp;thetas;) and Lx is the length of the horizontal axis of the detector)

.

The value of the length l _x2 to the edge (edge) near the x-ray source side of the oblique side of the X-ray irradiation window of the irradiation range adjusting device is,

(Where L _y '= tan θ · SDD and SDD is the distance between the source and the detector)

.

The value of the length l _x1 to the far side (edge) on the x-ray source side of the oblique side of the X-

.

Further, the present invention is such that the X-ray irradiation window of the irradiation range regulating apparatus is configured such that the X-ray tube moves in a trapezoidal shape having a longer length than the opposite direction, A driving method of a digital tomography image synthesizing system configured to adjust a size of an oblique side of an X-ray irradiation window of an irradiation range adjusting apparatus by adjusting a shape of an X-ray to be irradiated to a size of a detector, The height of the survey window (l _y )

l _y = l _y1 + l _y2

(Where, l _y1 = (a and d) / (L - b) and, l _y2 = (a and d) / (L + b), and, b = (a L _x and sinθ) / 2, a = L _x / (2 and cosθ) and, L _x is the length of the horizontal axis of the detector, θ is an angle of an X-ray sailor)

A height calculating step of the X-ray irradiation window obtained by the X-ray irradiation window; The control device sets the value of the length l _x2 to a side (edge) close to the x-ray source side of the oblique side of the X-ray irradiation window of the irradiation range adjusting device,

(Where L _y '= tan θ · SDD and SDD is the distance between the source and the detector)

Calculating a side length of the X-ray irradiation window near the source side; The control device sets the value of the length l _x1 to the far side (edge) on the x-ray source side of the oblique side of the X-ray irradiation window of the irradiation range adjusting device,

And calculating a length of a side far from the source of the X-ray irradiation window.

Between the height calculating step of the X-ray irradiating window and the calculating step of the X-ray irradiating window near the source side, the control device controls the height of the X-ray irradiating window of the irradiation range adjusting device obtained at the height calculating step of the X- may further include; l _y), to generate a control rod control signal, adjust the height of the window X-ray irradiation step, the irradiated area to be transmitted to the control unit according to.

Between the stage length calculation step near the source side of the X-ray irradiation window and the stage for calculating the far side length from the source side of the X-ray irradiation window, the control device is obtained in a stage length calculation step near the source side in the X- X-ray irradiating range of the apparatus for controlling the irradiation range x of the oblique side of the irradiation window x the length of a side (edge) near the source side l _x2 Generating a control rod control signal and transmitting the control rod control signal to the irradiation range control unit according to the X-ray irradiation control signal.

After the calculation step far from the source side of the X-ray irradiation window, the control device controls the X-ray source side of the X-ray irradiation window of the irradiation range adjusting device obtained at the far side length calculating step in the X- in accordance with the length l _x1 for the far side (edge), to generate a control rod control signal, x-ray irradiation window hypotenuse of the far side length adjusting step in x-ray source side, for transmitting to the irradiation range control section; an be achieved by further comprising: have.

The control device calculates the rotation angle of the x-ray source (that is, the angle (?) Of the X-ray source using the total rotation angle and the number of projections received from the input unit); An x-ray source coordinate calculation step for calculating X-ray source coordinate (S _x , S _y , S _z ), a detector movement path and a center coordinate calculation step for detecting a position (D _x , D _y , D _z ) .

In the x-ray source coordinate calculation step, the X-ray source coordinates are (0, S _y , SDD)

S _y = - (SDD-COR) x tan?

(Where SDD is the distance between the source and the detector and COR is the center of rotation)

.

In the detector movement path and center coordinate computation stage, the position of the detector is (0, D _y , 0) and D _y = -COR x tan ?.

According to the automatic variable irradiation range control device and the control method of the automatic variable irradiation range adjustment device of the digital tomography image synthesis system for chest radiography of the present invention, in the digital tomography image synthesis system, the variation of the direction in which the X- And a trapezoidal X-ray irradiating window formed to have a trapezoidal shape with a longer length than that of the X-ray irradiating range adjusting device, So that the patient dose can be reduced while obtaining the necessary information for the patient image.

The effects of the automatic variable irradiation range control device and the control method of the automatic variable irradiation range adjusting device of the digital tomography image synthesis system for chest radiography of the present invention are summarized as follows: (1) A digital tomography image synthesis system for chest radiography, By setting the scope of the investigation, it is possible to contribute to the optimal acquisition of the images and the reduction of the dose of the patient. ② By adjusting the automatic irradiation range according to each angle, the total image acquisition time can be reduced, , And ③ chest digital tomographic image synthesis system can be used to control not only the wide chest area but also other body parts such as knee joint, hand spine and sinus radiography, Reduces unnecessary patient dose when taking localized images And can, ④ can contribute to the industrialization and technology development of domestic shooting digital chest tomography yeosang synthesis system.

1 is a schematic diagram for explaining the structure and principle of a collimator.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an automatic variable irradiation range adjusting apparatus of a digital tomography image synthesizing system for chest radiography according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a schematic view for explaining a comparison between the conventional irradiation range adjusting device and the irradiation range adjusting device of the present invention.

FIG. 2 (a) shows a conventional irradiation range adjusting apparatus, and FIG. 2 (b) shows an irradiation range adjusting apparatus to be applied to the chest digital tomography image synthesizing system of the present invention.

The irradiation range adjusting device 120 of FIG. 2 (a) is an irradiation range adjusting device applied to a conventional general X-ray imaging system or a cone-beam CT system, and the X-ray irradiation window is formed of a rectangle or a square. Since the chest digital tomographic image synthesis system moves the X-ray tube linearly, X-rays are irradiated at a limited angle such as 30 and 50 degrees. Therefore, when the light is incident at an angle other than 0 degree, using a conventional irradiation range adjusting apparatus including a rectangular or square X-ray irradiating window, a trapezoidal beam is incident on the detector 200, Additional dose is investigated in the section. The additional dose beyond the detector is useless for the patient image to be generated and serves to increase the patient dose. In addition, the scattered rays generated in the off-beam enter the detector, and the contrast of the image is lowered.

The X-ray irradiating window of the variable irradiation range regulating apparatus 120 of the present invention shown in FIG. 2 (b) is such that the side 121 in the direction in which the X-ray tube moves is longer than the side 122 in the opposite direction It has a trapezoidal shape. The shape of the X-ray irradiated by the X-ray irradiation window of the trapezoidal irradiation range regulating apparatus 120 can be matched to the size of the detector 200, thereby reducing the dose of the patient while obtaining the information necessary for the patient image . That is, the trapezoidal irradiation range adjusting device adjusts the shape of the irradiated X-ray to the same shape as the detector.

FIG. 3 is an illustration of the geometry of the digital tomographic image synthesis system of the present invention.

FIG. 3 illustrates a method for acquiring an image of a predetermined size at all angles when using a chest digital tomography image synthesis system in which the X-ray source 110 and the detector 200 move in a straight line. In order to obtain an image of a constant size (L _x L _y ) according to the angle of the X-ray source, the lengths (l _x1 , l _x2 , l _y1 , l _y2 ) of the X- ) Can be obtained. The position of the detector can be expressed as (D _x , D _y , D _z ). The detector can be expressed as (0, D _y , 0) because it moves along the y-axis according to the angle of motion (θ) with the X-ray source. D _y is the distance from the detector to the center of rotation (COR) and the angle (θ)

D _y = -COR x tan?

Can be expressed as. The position of the X-ray source can be expressed as (S _x , S _y , S _z ). Considering that the distance between the source and the detector is fixed at the source-to-detector distance (SDD) along the Z-axis and does not move along the X-axis, it can be expressed as (0, S _y , SDD). S _y is obtained by subtracting COR from SDD and using angle (θ)

S _y = - (SDD-COR) x tan?

Can be expressed as.

Fig. 4 is a schematic diagram for explaining the process of obtaining the length l _y1 of the horizontal axis of the slope of the X-ray irradiation window of the irradiation range adjusting apparatus of the present invention.

4 is a view showing the height of the trapezoidal model of the X-ray irradiation window of the irradiation range adjusting device, that is, the length (l _y ) of the longitudinal axis of the detector. Let L be a distance from the X-ray source to the center of the detector vertically, and let d be the distance vertically passing through the center of the irradiation range adjusting device from the X-ray source. .

L = SDD / cos?

  (SDD = source to detector distance in Z direction)

The value of L _y , which is the longitudinal axis of the detector, is used to derive the values a and b together with the rotation angle (?) Of the X-ray tube at a fixed value by the detector size.

b = (L _x sin &thetas;) / 2

a = L _x / (2? cos?)

Here, b is a line that is perpendicular to the line connecting the X-ray source and the center of the detector as a first line, and when a line parallel to the first line and passing through the edge of the detector is referred to as a second line, The distance between lines. Also, a is the distance between the first line (the line perpendicular to the X-ray source and the line perpendicular to the detector center) and the detector edge.

l The value of _y1 can be obtained by deriving a distance a between the edge of the detector and a line perpendicular to the center of the X-ray source and the center of the detector, and then a proportional expression.

l _y1 = (a * d) / (L - b)

Fig. 5 is a schematic view for explaining the process of obtaining the length (l _y2 ) of the horizontal axis of the slope of the irradiation range adjusting apparatus of the present invention.

Similarly, the value of l _y2 can be obtained through a proportional equation after deriving the distance a between the edge opposite to the detector (that is, the opposite side) and the line perpendicular to the center of the detector and the X-ray source.

l _y2 = (a? d) / (L + b)

Finally, the value of the height l _y of the X-ray irradiation window can be obtained as the sum of l _y1 and l _y2 .

l _y = l _y1 + l _y2

6 is a schematic view for explaining a process of obtaining a length l _x2 of a slope of the irradiation range adjusting apparatus of the present invention.

The value of the length l _x2 of the slope of the irradiation range regulating device, that is, the value of the length l _x2 of the edge (edge) on the x-ray source side in the through hole (i.e., X- At the center of the crew l _x2 The edges (ie, l _x2 (I.e., the center of one side of the detector) at the center of the detector at the center of the source and the length passing through the center of the detector.

Here, L _y 'can be obtained from the following equation.

L _y '= tan? SDD

7 is a schematic diagram for explaining a process of obtaining a value of length l _x1 for a slope of the irradiation range adjusting apparatus of the present invention.

The length passing through the center of the l _x1 edge (l _x1 side) at the center of the source and the length passing through the center of the edge of the detector at the center of the source (i.e., the center of one side of the detector).

Fig. 8 is a schematic view showing an inside view of the irradiation range adjusting apparatus of the present invention.

The irradiation range regulating apparatus 120 of the present invention includes a plate 160 having a through hole (that is, an X-ray irradiation window) 150 for passing X-rays through the inside thereof, And a control stick 140 is attached to one side of the collimator blade 130. The collimator blade 130 is provided with a plurality of control sticks 140. The collimator blade 130 has a plurality of control sticks 140 attached thereto.

The control rod 120 is made up of a linear actuator (e.g., a linear motor), and by adjusting the length of each control rod 140, the collimator wing 130 can move up and down or have a specific angle.

The plate (160) and the collimator wing (130) are made of materials having a radiation shielding effect such as lead.

8A shows a case in which the two control rods 140 mounted on the respective collimator blades 130 are controlled to have the same length and the through holes 150 for passing X-rays are formed into a quadrangle.

8 (b) shows that the two control rods 140 mounted on the left and right collimator blades 130 are controlled to have the same length, and the two control rods 140 mounted on the upper and lower collimator blades 130 have different lengths So that the through hole 150 for passing the X-rays has a trapezoidal shape.

That is, the irradiation range adjusting device 120 of the present invention can change the shape of the irradiation range using a control stick 140 and can change the size of the detector 200, the distance from the source to the detector 200 The irradiation range is calculated according to information on the angle of rotation of the X-ray tube and the acquisition parameters, and the size of the opening 150 of the irradiation range adjusting device is adjusted by adjusting the control rod 140.

9 is a schematic diagram of a digital tomography image synthesis system for chest radiography equipped with an automatic variable irradiation range adjusting device of the present invention.

The digital tomographic image synthesis system includes an X-ray tube 12, a cassette 14, a moving mechanism 16, a moving mechanism 18, a controller 300, an irradiation range adjusting unit 120, an irradiation range controlling unit 125, An input unit 330, and a display unit 340.

The X-ray tube 12 outputs an X-ray (radiation) X at a predetermined dose in accordance with a control signal from the control device 300. [ The cassette 14 includes a radiation conversion panel and may be referred to as a detector 200. The cassette 14 detects the radiation X that has been emitted from the X-ray tube 12 and has passed through the object 26 (patient) of the imaging table 28 and converts the radiation X into radiation image information, To the control device 300. [ The moving mechanism 16 and the moving mechanism 18 move the X-ray tube 12 and the cassette 14 in accordance with the control signal of the controller 300. [

The irradiation range control unit 125 receives the control rod control signal from the imaging control unit 310 and adjusts the control rod 140 to set the size of the opening 150 of the irradiation range adjusting apparatus.

The photographing unit 32 performs photographing (for tomosynthesis) for digital tomographic image synthesis. The digital tomographic image synthesis shoot is to acquire data of a plurality of tomographic images (tomosynthesis tomographic images) for digital tomographic image synthesis on the assumption that reconstruction is performed.

The imaging control unit 310 operates the X-ray tube 12, the radiation conversion panel, the moving mechanisms 16 and 18, and the irradiation range control unit 125 to control shooting for digital tomographic image synthesis. The photographing control unit 310 calculates the irradiation range according to the size of the detector 200, the distance from the source to the detector 200, information on the angle of rotation of the X-ray tube, And transmits the generated control signal to the irradiation range control unit 125.

The image processing unit 320 performs predetermined processing, that is, image reconstruction, on the data of the tomosynthesis thin-layer image and outputs it to the display unit 340. [

The input unit 330 is a console for inputting a predetermined command from a medical professional such as a doctor at the time of tomosynthesis shooting, and includes key input means.

The display unit 340 outputs the video signal received from the control device 300. [

10 is a schematic flowchart of a digital tomography image synthesis system for chest radiography equipped with an automatic variable irradiation range adjusting device of the present invention.

In the initialization step, the user inputs system operation data, that is, the total rotation angle, the number of projections, and the like through the input unit 330. The controller 300, that is, the photographing control unit 310, That is, the total rotation angle, the number of projections, and the like (S105).

In the x-ray source moving step, the controller 300, that is, the photographing controller 310, generates an x-ray source movement and rotation control signal by using the received system operation data, that is, the total rotation angle, the number of projections, And the moving mechanism 16 linearly moves the x-ray source, that is, the X-ray tube 12 in accordance with the x-ray source movement and rotation control signal (S110) (S120).

In the detector moving step, the controller 300, that is, the photographing controller 310, generates the detector movement control signal by interlocking with the received system operation data or the x-ray source movement, and transmits the detector movement control signal to the movement mechanism 18 , The moving mechanism 18 linearly moves the detector 200 in accordance with the detector movement control signal (S130) and goes to the X-ray source irradiation step S300.

In the step of calculating the rotation angle of the x-ray source, the imaging control unit 310 calculates the rotation angle of the x-ray source (that is, the angle? of the X-ray source) based on the received total rotation angle and the number of projections S210).

(S _x , S _y , S _z ) of an X-ray source coordinate, that is, the position of an X-ray source in operation S220. Here, in view of the prior application and the detector distance point and is that it does not move in the X-axis that is fixed at a SDD (source-to-detector distance ) in the Z-axis is represented by (0, S _y, SDD), S _y is Is obtained by subtracting COR from SDD and S _y = - (SDD-COR) x tan θ using angle (θ).

The position (D _x , D _y , D _z ) of the detector is detected by the detector moving path and the center coordinate calculation step (S230). Here, the detector can be expressed as (0, D _y , 0) because the detector moves along the y axis according to the moving angle (θ) with the X-ray source and D _y is the distance from the detector to the center of rotation Using the angle?, D _y = -COR x tan ?.

The height (l _y ) of the irradiation range adjusting device (collimator), more specifically, the height of the through hole of the irradiation range adjusting device (collimator) is calculated (S240) as a height calculating step of the collimator. Here, the height (ly) of the irradiation range adjustment device (collimator) will seek the sum of l _y1 and l _y2, l _y1 = (a and d) / (L - b) and, l _y2 = (a and d) / (L + b), b = (L _x sin &thetas;) / 2, and a = L _x / (2 cos &thetas;).

The control device 300 controls the height of the collimator wing 130 in accordance with the height ly of the irradiation range adjusting device (collimator) obtained in the height calculating step of the collimator, And transmits it to the irradiation range control unit 125. The irradiation range control unit 125 causes the control rod 120 to operate in accordance with the control rod control signal (S250).

(Corner) calculation step of the collimator close to the x-ray source side, the value of the length l _x2 to the side of the collimator close to the x-ray source side (that is, ) &_Lt; / RTI > of length l _x2 )

(Provided that L _y '= tan? SDD)

.

the controller 300 controls the length of the collimator near the x-ray source side, and the control device 300 controls the length of the collimator near the x-ray source, which is obtained at the corner calculating step of the collimator near the x- A control rod control signal for controlling the control rod 120 related to the length of the collimator near the x-ray source side is generated according to the value of the length l _{x2 for} the irradiation range control unit 125, The range control unit 125 drives the control rod 120 according to the control rod control signal (S270).

x is the length of the collimator on the x-ray source side, and the value of the length l _x1 (that is, the value on the opposite side of the x-ray source side in the through- The value of the length l _x1 )

(S280).

the controller 300 controls the length of the distal end of the collimator on the x-ray source side, and the control device 300 controls the length of the distal end of the collimator near the x-ray source side obtained in the arithmetic operation step of the distal collimator on the x- for in accordance with the value of length l _x1, it generates a control rod a control signal for controlling the control rod 120 is related to the length of the sides (edges) of the near collimation in the x-ray source side, and sent to the irradiation range control section 125, the irradiation The range control unit 125 drives the control rod 120 in accordance with the control rod control signal (S290).

In the x-ray irradiation step, the x-ray source and the detector are moved to prepare for emitting x-rays, the length of the through hole inside the irradiation range regulating device 120 is adjusted, and x-rays are emitted (S300).

 Although the preferred embodiments of the present invention have been described in detail, the present invention is not limited thereto, and various other changes and modifications may be made.

12: X-ray tube 14: Cassette
16, 18: moving mechanism 26: object to be inspected (patient)
28: photographing stand 32: photographing unit
110: X-ray source 120: Irradiation range adjuster
121, 122: SIDE 125:
130: collimator wing 140: control rod
150: through hole 160: plate
200: detector 300: control device
310: photographing control unit 320: image processing unit
330: input unit 340: display unit

Claims (16)

An X-ray source for irradiating the X-ray source, an irradiation range adjusting device for adjusting the shape and size of the beam emitted from the X-ray source, a detector for detecting the projected X-ray projection image from the X- A digital tomographic image synthesis system comprising a control device for controlling movement of a detector,
Wherein the X-ray irradiating window of the irradiation range regulating device is configured to have a trapezoidal shape in which the X-ray tube moves in a direction in which the X-ray tube moves is longer than the side in the opposite direction. The method according to claim 1,
Wherein the control device adjusts the size of the oblique side of the X-ray irradiation window of the irradiation range adjusting device by adjusting the shape of the X-ray irradiated to the patient to the size of the detector. 3. The method of claim 2,
The irradiation range adjusting device includes a plate having an X-ray irradiating window for passing X-rays inside, and a collimate blade is provided on each of the upper, lower, left, and right sides of the rim of the X- Wherein two or more control sticks are mounted on one side of the collimator wing. The method of claim 3,
Wherein the control rod is composed of a linear actuator, and the length of each control rod is adjusted so that the collimator wing moves up and down or has a specific angle. The method of claim 3,
The control device adjusts the irradiation range of the irradiation range adjusting device by obtaining the length of the X-ray irradiation window of the irradiation range adjusting device to obtain a predetermined size image according to the angle of the X-ray source Digital tomographic image synthesis system. 6. The method of claim 5,
The control device receives the system operation data including the total rotation angle and the number of projections from the input unit, obtains the rotation angle (?) Of the x-ray source, and adjusts the irradiation range A length of each side of the X-ray irradiation window of the apparatus is obtained, a control rod control signal is generated in accordance with the length of each side of the X-ray irradiation window,
And the irradiation range control unit controls the control rod. The method according to claim 6,
The height (l _y ) of the X-ray irradiation window of the irradiation range regulating device
l _y = l _y1 + l _y2
(Where, l _y1 = (a and d) / (L - b) and, l _y2 = (a and d) / (L + b), and, b = (a L _x and sinθ) / 2, a = L _x / (2cos &_amp;thetas;) and Lx is the length of the horizontal axis of the detector)
And the digital tomographic image synthesizing system. 8. The method of claim 7,
The value of the length l _x2 to the edge (edge) near the x-ray source side of the oblique side of the X-ray irradiation window of the irradiation range adjusting device is,

(Where L _y '= tan θ · SDD and SDD is the distance between the source and the detector)
And the digital tomographic image synthesizing system. 9. The method of claim 8,
The value of the length l _x1 to the far side (edge) on the x-ray source side of the oblique side of the X-

And the digital tomographic image synthesizing system. In the X-ray irradiation window of the irradiation range regulating apparatus, a variation in the direction of movement of the X-ray tube takes a trapezoidal shape having a longer length than that of the opposite direction, and the control device controls the shape of the X- A method of driving a digital tomography image synthesis system configured to adjust a size of a subject of an X-ray irradiation window of an irradiation range adjusting device in accordance with a size of a detector,
The control device controls the height (l _y ) of the X-ray irradiation window of the irradiation range adjusting device to
l _y = l _y1 + l _y2
(Where, l _y1 = (a and d) / (L - b) and, l _y2 = (a and d) / (L + b), and, b = (a L _x and sinθ) / 2, a = L _x / (2 and cosθ) and, L _x is the length of the horizontal axis of the detector, θ is an angle of an X-ray sailor)
Calculating a height of the X-ray irradiating window;
The control device sets the value of the length l _x2 to a side (edge) close to the x-ray source side of the oblique side of the X-ray irradiation window of the irradiation range adjusting device,

(Where L _y '= tan θ · SDD and SDD is the distance between the source and the detector)
Calculating a side length of the X-ray irradiation window near the source side;
The control device sets the value of the length l _x1 to the far side (edge) on the x-ray source side of the oblique side of the X-ray irradiation window of the irradiation range adjusting device,

Calculating a distance between the X-ray irradiation window and the source side;
Wherein the digital tomographic image synthesizing system comprises: 11. The method of claim 10,
Between the height calculation step of the X-ray irradiation window and the side length calculation step near the source side of the X-ray irradiation window,
The control device controls the height of the X-ray irradiation window to generate a control rod control signal in accordance with the height (l _y ) of the X-ray irradiation window of the irradiation range adjusting device obtained in the height calculating step of the X- step;
And outputting the digital tomographic image synthesized by the digital tomographic image synthesizing system. 12. The method of claim 11,
Between the X-ray irradiation window and the far side length calculation step of the X-ray irradiation window,
It controls the length of the side close to the X-ray irradiation window oblique x-ray source side of the irradiation range adjustment Jin obtained in the near side length calculation step to crew side of the X-ray irradiation window (corner) l _x2 A side length control step of generating a control rod control signal and transmitting the control signal to the irradiation range control unit, the side length close to the x-ray source side of the X-ray irradiation window;
And outputting the digital tomographic image synthesized by the digital tomographic image synthesizing system. 13. The method of claim 12,
After the calculation of the length of the far side on the source side of the X-ray irradiation window,
The control device controls the control rod control signal (X-ray control signal) according to the length l _x1 to the far side (edge) on the x-ray source side of the X-ray irradiation window of the irradiation range adjusting device obtained at the far side length calculating step on the source side of the X- And controlling the far side length to the x-ray source side of the X-ray irradiation window to be transmitted to the irradiation range control unit;
And outputting the digital tomographic image synthesized by the digital tomographic image synthesizing system. 14. The method of claim 13,
The control device calculates the rotation angle of the x-ray source (that is, the angle (?) Of the X-ray source using the total rotation angle and the number of projections received from the input unit);
An x-ray source coordinate calculation step of calculating X-ray source coordinate (S _x , S _y , S _z );
A detector movement path and a center coordinate calculation step for detecting the position (D _x , D _y , D _z ) of the detector;
And outputting the digital tomographic image synthesized by the digital tomographic image synthesizing system. 15. The method of claim 14,
In the x-ray source coordinate calculation step, the X-ray source coordinates are (0, S _y , SDD)
S _y = - (SDD-COR) x tan?
(Where SDD is the distance between the source and the detector and COR is the center of rotation)
Wherein the digital tomographic image synthesizing system comprises: 16. The method according to claim 15, wherein in the detector movement path and center coordinate computation step,
The position of the detector is (0, D _y , 0)
D _y = -COR x tan?
Wherein the digital tomographic image synthesizing system comprises:

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