WO2020209568A1

WO2020209568A1 - System and method for evaluating motion of radiation diagnosis and treatment device

Info

Publication number: WO2020209568A1
Application number: PCT/KR2020/004659
Authority: WO
Inventors: 한영이; 조광현; 천원중
Original assignee: 사회복지법인 삼성생명공익재단
Priority date: 2019-04-08
Filing date: 2020-04-07
Publication date: 2020-10-15
Also published as: KR102223769B1; KR20200118719A

Abstract

The present invention provides a system for evaluating motion of a radiation diagnosis and treatment device, comprising: a gantry having a cylindrical opening in the center thereof and rotatable in the circumferential direction of the opening; a marker unit installed on the gantry and including at least one marker; a camera unit including a plurality of cameras for photographing the at least one marker; a coordinate calculator for calculating a plurality of coordinates on a rotation trajectory of the at least one marker on the basis of marker images captured by the plurality of cameras when the gantry rotates; and an inspection unit for inspecting the positional accuracy of a first isocenter of the gantry by using the calculated coordinates.

Description

Motion evaluation system and method of radiation diagnosis and treatment device

Embodiments of the present invention relate to a system and method for motion evaluation of a radiation diagnosis and treatment apparatus, and more particularly, to evaluate the precision of the rotational motion of the gantry, and to align the rotational center of the gantry to a target position of the radiation target. It relates to a system and method for motion evaluation of a radiological diagnosis and treatment device.

As medical technology develops, medical devices that assist in diagnosis and treatment are becoming increasingly sophisticated. For example, in cancer treatment, conventionally, surgery, medication and/or treatment by radiation such as electromagnetic waves, cobalt, and radium was the mainstream, but recently, a particle ray treatment device that irradiates and treats particle rays, which are special radiations represented by quantum rays or carbon rays. Was developed. Treatment by the particle ray therapy device is characterized by being non-invasive, and has the advantage of enabling rapid recovery of the patient after treatment.

If the patient on the bed or couch is not accurately positioned at the target point in the radiation treatment and diagnostic radiography apparatus for the same, in the case of surrounding tissues with high radiation sensitivity, organ damage may be caused due to unplanned radiation dose. . Therefore, the position of the patient relative to the radiation diagnosis and treatment device needs to be precisely controlled.

Meanwhile, in the related art, a graphic paper, a laser, a goniometer, and the like have been used to evaluate the drive of a gantry irradiating radiation or to evaluate the positional accuracy of a bed to transport a patient. However, since these methods rely only on human visual judgment, it is difficult to objectively evaluate the precision of the motion of each gantry and bed, and the positional relationship between the gantry and bed.

The present invention is to solve various problems, including the above problems, of a radiation diagnosis and treatment apparatus capable of evaluating the precision of the rotational motion of the gantry and aligning the rotational center of the gantry with the target position of the radiation target. It is an object to provide a motion evaluation system and method. However, these problems are exemplary, and the scope of the present invention is not limited thereby.

According to an aspect of the present invention, a gantry having a cylindrical opening in the center and rotatable in the circumferential direction of the opening, a marker unit installed on the gantry and including at least one marker, for photographing the at least one marker A camera unit including a plurality of cameras, a coordinate calculation unit that calculates a plurality of coordinates on a rotation trajectory of the at least one marker based on the marker images captured by the plurality of cameras when the gantry is rotated, and the calculated A motion evaluation system for a radiation diagnosis and treatment apparatus is provided, including an inspection unit for inspecting a positional accuracy of a first isocenter of the gantry using a plurality of coordinates.

The first isocenter may be a rotation center of the gantry.

The inspection unit receives coordinate values of the plurality of coordinates and extracts a plurality of representative coordinates from among the plurality of coordinates, and selects a predetermined number of arbitrary coordinates from among the plurality of extracted representative coordinates. An operation unit that calculates the isocentric coordinates of a virtual circle passing through arbitrary coordinates, and obtains a plurality of isocentric coordinates by calculating the isocentric coordinates of the virtual circle multiple times, and the obtained plurality of isocentric coordinates 1 It may be provided with an output unit for outputting the distance between the estimated coordinates of the center of gravity.

The plurality of representative coordinates may include coordinates of positions spaced at a predetermined angle along the circumferential direction of the opening on the rotation orbit.

The predetermined number may be at least three.

The first isocenter estimation coordinate may be a center of gravity coordinate calculated by using the plurality of isocenter coordinates as a material point.

The output unit may output a distance between each of the plurality of isocentric coordinates and the first isocentric estimated coordinate in the form of a graph or numerical value.

The inspection unit may further include a determination unit, and the determination unit may determine whether a distance between each of the plurality of isocentric coordinates and the first isocentric estimated coordinate is less than or equal to a preset value.

The at least one marker may be disposed outside the opening on one surface extending in a direction transverse to the center of the opening of the gantry.

Each of the plurality of cameras may be arranged to face different positions of the gantry.

The at least one marker may include an infrared marker, and the plurality of cameras may include an infrared camera.

A body portion disposed on the bed portion and a bed portion disposed to be inserted into the opening, and having a first surface and a second surface opposite to the first surface, and on the first surface of the body portion A correction marker unit including a plurality of correction markers positioned to be spaced apart from each other may be further provided.

A first coordinate system defining the real coordinates and the image coordinates are defined using real coordinates of the plurality of correction markers and image coordinates calculated from an image photographed of the plurality of correction markers by the plurality of cameras. A coordinate conversion unit for deriving a conversion relationship between the second coordinate systems may be further provided.

A laser oscillation unit may be further provided to irradiate a laser beam to the center of the first surface to display a second isocenter, which is a reference point of the first coordinate system.

The inspection unit may further include a determination unit, and the determination unit may determine whether the second isocenter of the correction marker unit is aligned with the first isocenter of the gantry.

The second surface may face the gantry.

According to another aspect of the present invention, the step of installing a marker unit including at least one marker on a gantry having a cylindrical opening in the center and rotatable in a circumferential direction of the opening, the camera unit including a plurality of cameras Taking at least one marker, calculating a plurality of coordinates on the rotation trajectory of the at least one marker based on the marker images captured by the plurality of cameras when the gantry rotates, and the calculated plurality of A method for evaluating a motion of a radiation diagnosis and treatment apparatus is provided, comprising the step of examining the positional precision of the first isocenter of the gantry using coordinates.

The checking of the positional precision may include receiving coordinate values of the plurality of coordinates and extracting a plurality of representative coordinates among the plurality of coordinates, and a predetermined number of arbitrary coordinates among the extracted plurality of representative coordinates. Selecting and calculating the isocentric coordinates of the virtual circle passing through the selected arbitrary coordinates, calculating the isocentric coordinates of the virtual circle a plurality of times to obtain a plurality of isocentric coordinates, and the obtained plurality It may include the step of outputting the distance between the isocenter coordinates and the first isocentric estimated coordinates.

The predetermined number may be at least three.

The first isocenter estimation coordinate may be a center of gravity coordinate calculated by using the plurality of isocenter coordinates as a mass point.

The outputting of the distance may be a step of outputting a distance between each of the plurality of isocentric coordinates and the first isocentric estimated coordinate in the form of a graph or numerical value.

The checking of the positional accuracy may include determining whether a distance between each of the plurality of isocentric coordinates and the first isocentric estimated coordinate is less than or equal to a preset value.

The step of checking the positional accuracy may include determining whether a second isocenter of the correction marker unit disposed on the bed part insertable into the opening is aligned with the first isocenter of the gantry. I can.

The correction marker unit includes a body portion having a first surface and a second surface opposite to the first surface, and a plurality of correction markers spaced apart from each other on the first surface of the body portion, and the first The second isocenter can be displayed by irradiating a laser beam on the center of the surface.

The second surface may face the gantry.

According to an embodiment of the present invention made as described above, it is possible to objectively evaluate the precision of the rotational motion of the gantry.

In addition, it is possible to evaluate in advance whether the center of rotation of the gantry is aligned with the patient's affected area, etc., so that appropriate measures can be taken to prevent the patient from being exposed to unplanned radiation.

Of course, the scope of the present invention is not limited by these effects.

1 is a perspective view schematically showing a motion evaluation system of a radiation diagnosis and treatment apparatus according to an embodiment of the present invention.

2 is an enlarged view schematically showing the correction marker of FIG. 1.

3 is a block diagram schematically illustrating a motion evaluation system of a radiation diagnosis and treatment apparatus according to an embodiment of the present invention.

4 is a diagram illustrating an example in which a plurality of coordinates on a rotation trajectory of a gantry marker are calculated by a motion evaluation system of a radiation diagnosis and treatment apparatus according to an embodiment of the present invention.

5 is a diagram illustrating an example in which a plurality of coordinates for estimating isocentric coordinates of a gantry are calculated by a motion evaluation system of a radiation diagnosis and treatment apparatus according to an embodiment of the present invention.

6 is a histogram showing the number of distributions of points O2 according to the distance d of FIG. 5.

7 is a flowchart sequentially illustrating a motion evaluation method of a radiation diagnosis and treatment apparatus according to an embodiment of the present invention.

Since the present invention can apply various transformations and have various embodiments, specific embodiments are illustrated in the drawings, and will be described in detail in the detailed description. However, this is not intended to limit the present invention to a specific embodiment, it is to be understood to include all conversions, equivalents, and substitutes included in the spirit and scope of the present invention. In describing the present invention, when it is determined that a detailed description of a related known technology may obscure the subject matter of the present invention, a detailed description thereof will be omitted.

Terms such as first and second used in the present specification may be used to describe various components, but the components should not be limited by terms. The terms are only used for the purpose of distinguishing one component from another component.

The x-axis, y-axis, and z-axis used in the present specification are not limited to three axes on a Cartesian coordinate system, and may be interpreted in a broad sense including them. For example, the x-axis, y-axis, and z-axis may be orthogonal to each other, but may refer to different directions that are not orthogonal to each other.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings, and in the description with reference to the drawings, substantially identical or corresponding components are given the same reference numbers, and redundant descriptions thereof will be omitted. do. In the drawings, the thicknesses are enlarged to clearly express various layers and regions. In addition, in the drawings, the thicknesses of some layers and regions are exaggerated for convenience of description.

1 is a perspective view schematically showing a motion evaluation system of a radiation diagnosis and treatment apparatus according to an embodiment of the present invention, and FIG. 2 is an enlarged view schematically showing a correction marker unit of FIG. 1.

1 and 2, a motion evaluation system 10 of a radiation diagnosis and treatment apparatus according to an embodiment of the present invention includes a gantry 110, a marker unit 120, a camera 130, and a coordinate calculation unit ( 140) and an inspection unit 150. In addition, the motion evaluation system 10 of the radiation diagnosis and treatment apparatus may further include a correction marker unit 124, a laser oscillation unit 125, a bed unit 126 and.

First, the gantry 110 has a cylindrical opening 105 at the center and can rotate in the circumferential direction of the opening 105. The gantry 110 may be supported by the housing 101 surrounding the outer circumferential surface of the gantry 110, and a radiation source (not shown) for generating radiation is provided on the inner surface of the opening 105. Accordingly, when a radiation target body (not shown) is introduced into the opening 105 of the gantry 100, the gantry 110 radiates the radiation to the target body while rotating around the target body at a constant speed. In this case, the radiation irradiated to the irradiated object may include X-rays, gamma rays, high-energy electrons, high-energy protons, or other high-energy particle rays.

A marker unit 120 is installed on the gantry 110. In one embodiment, the marker unit 120 is installed on one surface extending in a direction transverse to the center of the opening 105 of the gantry 110, as shown in FIG. 1, to be disposed outside the opening 105 I can. In another embodiment, the marker unit 120 may be disposed on the inner surface of the opening 105, specifically, the marker unit 120 may be disposed at the center of the inner surface of the cylindrical opening 105. In this case, the marker unit 120 is located at an intermediate point of the cylindrical wall of the opening 105, so that the precision of the rotational motion of the gantry 110 at the central portion of the bed unit 126 can be evaluated. At this time, the affected part of the patient may be approximately located in the central part of the bed part 126. Hereinafter, for convenience of description, the case where the marker unit 120 is disposed outside the opening 105 will be described in detail.

The marker unit 120 may include at least one marker 121. In FIG. 1, the marker unit 120 is shown to include one marker 121, but the marker unit 120 may include a plurality of markers, and the plurality of markers may be disposed to be spaced apart from each other. . In this case, the plurality of markers may be arranged adjacent to each other to form a shape such as a triangle or a square by connecting to each other, or may be arranged to be spaced apart from each other along the perimeter of the opening 105. Hereinafter, for convenience of description, the case where the marker unit 120 includes one marker 121 will be described in detail.

As the gantry 110 rotates, the marker 121 rotates together with the gantry 110. Accordingly, the marker 121 is rotated to form a rotational trajectory R having a shape similar to the opening 105, and the rotation of the marker 121 is photographed by a plurality of cameras 130 to be described later, and the gantry ( 110) can be used as data to evaluate the precision of rotational motion.

The camera unit includes a plurality of cameras 130 for photographing the marker 121. In this case, the number of cameras 130 may be at least three or more. Each of the plurality of cameras 130 may be disposed to face different positions of the gantry 110. That is, each lens of the plurality of cameras 130 may be arranged to focus on different positions of the gantry 110.

There may be various ways in which the plurality of cameras 130 recognize the marker 121, for example, a passive marker that tracks the position of the marker by reflecting light such as infrared light to the marker by adding additional equipment other than the camera ( passive maker) method and active marker method in which the camera tracks the marker position by emitting light directly from the marker. In the present embodiment, the marker 121 may be a passive marker that reflects infrared rays emitted from a separate infrared generating device (not shown) as an infrared marker, and the camera 130 is an infrared camera that recognizes the reflected infrared rays. I can.

When the marker 121 is an infrared marker, there may be various methods for the camera 130 to recognize the marker 121. As one of them, the camera 130 photographs the marker 121 when infrared rays irradiated from various directions are reflected by the marker 121, and a circle fitting method is performed by detecting brightly shining pixels in the acquired image. After finding a suitable circle through, there may be a method of recognizing the center coordinates of the suitable circle as the location of the marker 121. As another method, when infrared rays irradiated from various directions are reflected by the marker 121, the marker 121 is photographed by the camera 130, and the brightest pixel among the acquired images is detected. The coordinates of the pixels may be recognized as the location of the marker 121.

Using the above-described methods, based on the marker 121 image generated by the plurality of cameras 130 photographing the marker 121 moving on the rotational trajectory R, the coordinate calculation unit 140 includes the marker 121 ) To calculate a plurality of coordinates corresponding to a plurality of positions on the rotational orbit R.

The coordinate calculation unit 140 calculates the three-dimensional coordinates of the marker 121 based on the CCD information of the plurality of cameras 130, and the algorithm used at this time is a motion capture algorithm such as DLT (direct linear transformation) and NDLT ( non-linear direct transformation), etc.

A plurality of three-dimensional coordinates calculated by the coordinate calculation unit 140 are input to the inspection unit 150 and are used to check the precision of the rotational movement of the gantry 110. At this time, the precision of the rotational motion of the gantry 110 is checked by checking the positional accuracy of the first isocenter corresponding to the driving center or rotation center of the gantry 110. The inspection unit 150 may include a coordinate input unit, an operation unit, an output unit, and a determination unit, which will be described later with reference to FIG. 3 and the like.

Meanwhile, the bed portion 126 may be disposed to face the gantry 110. The bed portion 126 may be positioned at a height corresponding to the center of the opening 105 so that the top portion of the bed portion 126 may be inserted into the opening 105.

On the top of the bed part 126, the patient can lie down, and the bed part 126 may move in the left and right directions and/or in the up and down directions so that radiation can be irradiated to the affected part of the patient, You can also rotate it.

A correction marker part 124 may be disposed on the bed part 126. The correction marker unit 124 may include a plurality of correction markers 122 and a body portion 123. The body part 123 has a first surface S1 and a second surface S2 that is opposite to the first surface S1, and the first surface S1 and the second surface S2 are substantially parallel to each other. I can. The second surface S2 is a surface facing the gantry 110 and may be disposed to be substantially parallel to a surface on which the marker unit 120 of the gantry 110 is disposed.

For example, the body part 123 may have a shape such as a regular cube or a rectangular parallelepiped. The length of each edge of the body portion 123 is known information, and the body portion 123 may be formed of a hard material such that the length of each edge is not easily changed by an external force.

A plurality of correction markers 122 may be disposed on the first surface S1 of the body part 123. The plurality of correction markers 122 may be disposed to be spaced apart from each other. For example, the plurality of correction markers 122 may be disposed adjacent to each vertex of the body part 123. 1 illustrates that four correction markers 122 are disposed on the first surface S1, but the present invention is not limited thereto, and three or more correction markers 122 are sufficient.

Similar to the length of the edge of the body part 123 described above, the distances between the plurality of correction markers 122 correspond to known information. Among the separation distances, the distances between the first surface S1 and the second surface S2 are used as the distances respectively corresponding to the horizontal and vertical of the first surface S1 and the edge length of the body 123 Thus, 3D reality coordinates of the plurality of correction markers 122 may be calculated. Here, the real coordinates mean actual coordinates of the plurality of correction markers 122 in a treatment room in which the gantry 110, the bed unit 126, and the like are disposed. At this time, in order to calculate the real coordinates of the plurality of correction markers 122, the center (C0) of the first surface (S1) of the correction marker unit 124 is a reference point, for example, (0, 0, 0), which is the origin of the three-dimensional coordinates. Can be set to Thereby, 4 coordinates of the plurality of correction markers 122 located on the first surface S1, the other 4 coordinates located on the second surface S2 to correspond to the 4 coordinates, and a total of 8 real coordinates Can be calculated.

These plurality of correction markers 122 are photographed by a plurality of cameras 130 to generate a correction marker image, and the three-dimensional image coordinates of the plurality of correction markers 122 are calculated based on the correction marker image. . In this case, the method of calculating the 3D image coordinates is the same as or similar to the method of calculating the 3D coordinates based on the image of the marker 121 described above.

Meanwhile, the image coordinates may be composed of eight coordinates corresponding to the real coordinates, whereby a transformation relationship between the image coordinates and the real coordinates can be easily derived. For example, as shown in FIG. 2, the coordinates of the center of the first surface S1 are (0, 0, 0), and the separation distance of the correction markers 122 in the x-axis direction and the separation in the y-axis direction When the distances are respectively d1 and d2, and the distance between the first and second surfaces S1 and S2 of the body 123 is w, the coordinate values of the eight coordinates are d1, d2 and w It can be expressed as That is, the first coordinate (A1) is (-d1/2, -d2/2, 0), the second coordinate (A2) is (-d1/2, d2/2, 0), and the third coordinate (A3) is (d1/2, d2/2, 0), the fourth coordinate (A4) is (d1/2, -d2/2, 0), the fifth coordinate (A5) is (-d1/2, -d2/2, -w), the sixth coordinate (A6) is (-d1/2, d2/2, -w), the seventh coordinate (A7) is (d1/2, d2/2, -w), the eighth coordinate (A8 ) Can be represented as (d1/2, -d2/2, -w), respectively.

The real coordinates and the image coordinates are input to a coordinate conversion unit 160, and the coordinate conversion unit 160 uses the input coordinates to define a first coordinate system for defining the real coordinates and a first coordinate system for defining the image coordinates. The transformation relationship between the two coordinate systems is derived. At this time, the center C0 of the first surface S1 becomes a reference point of the first coordinate system.

In an embodiment, the first coordinate system and the second coordinate system may be expressed as a matrix as shown in Equation 1 below.

[Equation 1]

V = [V ₁ V ₂ V ₃ V ₄ V ₅ V ₆ V ₇ V ₈ ]

R = [R ₁ R ₂ R ₃ R ₄ R ₅ R ₆ R ₇ R ₈ ]

Here, R means a first matrix representing the first coordinate system, and V means a second matrix representing the second coordinate system.

The first matrix, the second matrix, and T, which is a third matrix representing the transformation relationship, satisfy Equation 2 below.

[Equation 2]

R=TVR=TV

Therefore, the third matrix T can be derived using Equation 3 below.

[Equation 3]

T=RV ^-1

As described above, by using the third matrix derived by multiplying the first matrix by the inverse matrix of the second matrix, real coordinates of the irradiated object are calculated from the image coordinates of the irradiated object disposed on the bed part 126 I can do it. Accordingly, it is possible to objectively evaluate the actual movement of the irradiated object in a space called a treatment room through information obtained by analyzing the image coordinates of the irradiated object.

The laser beam LB may be irradiated to the center of the first surface S1 of the correction marker unit 124. To this end, the laser oscillation unit 125 may be disposed to face the first surface S1. Specifically, the laser beam LB is irradiated to the center C0 of the first surface S1 of the correction marker unit 124 in order to display the reference point of the first coordinate system that defines the real coordinates of the treatment room space. Here, the reference point of the first coordinate system corresponds to the second isocenter, which is the location of the affected part of the patient disposed on the bed part 126.

3 is a block diagram schematically showing a motion evaluation system of a radiation diagnosis and treatment apparatus according to an embodiment of the present invention, and FIG. 4 is a motion evaluation system of a radiation diagnosis and treatment apparatus according to an embodiment of the present invention. A diagram showing an example in which a plurality of coordinates on the rotation trajectory of the gantry marker are calculated, and FIG. 5 is a diagram illustrating an isocentric coordinate of a gantry by a motion evaluation system of a radiation diagnosis and treatment apparatus according to an embodiment of the present invention. A diagram showing an example in which a plurality of coordinates are calculated, and FIG. 6 is a histogram showing the number of distributions of points O2 according to the distance d of FIG. 5.

Referring to FIGS. 3 to 6 and the above-described FIGS. 1 and 2 together, the inspection unit 150 for checking the positional accuracy of the first isocenter corresponding to the driving center or rotation center of the gantry 110 is a coordinate input unit. 151, an operation unit 152, an output unit 153, and a determination unit 154 may be provided.

As described above, on the basis of the image of the marker 121 captured by the plurality of cameras 130, the coordinate calculation unit 140 corresponds to a plurality of positions on the rotation trajectory R of the marker 121. When the coordinates are calculated, the calculated 3D coordinate values of the plurality of coordinates are input to the coordinate input unit 151.

The coordinate input unit 151 extracts a plurality of representative coordinates from among the plurality of input coordinates. In one embodiment, the plurality of representative coordinates may include coordinates of positions spaced apart from each other by a predetermined angle along the circumferential direction of the opening 105 on the rotation orbit R. Accordingly, when the gantry 110 rotates, position information of the marker 122 per predetermined time interval can be obtained, so that the precision of the constant velocity rotational motion of the gantry 110 can be effectively evaluated. In addition, since coordinates that may be imaginary numbers are filtered, reliability of motion evaluation of the gantry 110 may be improved.

Referring to the example shown in FIG. 4 for better understanding, the plurality of representative coordinates P may be 36. That is, the plurality of representative coordinates (P) may be coordinates of a position separated by a certain angle (α) on the rotation trajectory (R) of the marker 121, at this time, the angle α separated from the neighboring coordinates is 10 degrees. do. Meanwhile, the rotation center coordinate O1 of the rotation trajectory R of the marker 121 may be different from the geometric center of the opening 105. That is, when the gantry 110 rotates, the rotation trajectory of the marker 121 does not geometrically become a true circle, and may become a circle that is partially distorted due to deflection and vibration of the gantry 110, and thus the gantry The rotation center coordinate O1, which is the first equicenter of 110, may be different from the geometric center of the rotation orbit R.

Using the plurality of representative coordinates P extracted by the coordinate input unit 151, the calculation unit 152 calculates a plurality of candidate coordinates of the first isocenter. In an embodiment, first, a certain number of arbitrary coordinates is selected from among a plurality of representative coordinates (P), and isocentric coordinates of a virtual circle passing through the selected arbitrary coordinates are calculated. Thereafter, the process of selecting arbitrary coordinates as described above is repeated a plurality of times to calculate the isocentric coordinates of a plurality of virtual circles, and each of the calculated isocentric coordinates of the plurality of virtual circles is immediately a candidate of the first isocenter. It becomes the coordinates. Here, the isocentric coordinate of the virtual circle means the geometric center of the virtual circle.

Referring back to the example shown in FIG. 4, first, three coordinates are randomly selected from among a plurality of representative coordinates P. The reason why three coordinates are selected here is because the minimum number of coordinates necessary to obtain a circle is three. Therefore, the number of selected coordinates among the plurality of representative coordinates (P) may be greater than three, but for convenience of explanation below, three arbitrary coordinates (P1, P2, P3) among the plurality of representative coordinates (P) It will be described in detail focusing on the case of selecting ).

After selecting three arbitrary coordinates (P1, P2, P3) in this way, the isocentric coordinates of the virtual circle (V) passing through the coordinates (P1, P2, P3) are calculated. Here, the isocentric coordinate of the virtual circle V means the coordinate O2 of the geometric center of the virtual circle V.

Thereafter, the process of selecting three arbitrary coordinates is repeated as described above. In order to obtain as many isocentric coordinates of the virtual circle as possible, the isocentric coordinates of the virtual circle corresponding to the number of cases can be calculated. At this time, since the number of all cases of selecting three arbitrary coordinates is 14,280, which is a value obtained by calculating 36C3, which is a combination formula, a total of 14,280 isocentric coordinates of the virtual circle that can be obtained by repeating the above-described process. A distribution diagram in which each of the isocenter coordinates of the virtual circle acquired together is indicated by a red circle is shown.

The first isocentric coordinates are calculated by using the plurality of isocentric coordinates calculated by the calculation unit 152, and then the output unit 153 calculates the calculated plurality of isocentric coordinates and the first isocenter estimation Print the distance between coordinates. Here, the first isocenter estimation coordinate means a coordinate estimated as the rotation center coordinate O1 of the rotation orbit R, where the rotation orbit R is the deflection and vibration of the gantry 110 as described above. It may have a circular shape that is partially distorted due to the like.

In an embodiment, the first isocenter estimation coordinate may be a center of gravity coordinate calculated by using a plurality of isocenter coordinates calculated by the calculation unit 152 as a material point. Referring to the example shown in FIG. 5, the center of gravity coordinate O1 ′ calculated by using red circles representing each of 14,280 isocenter coordinates as a mass point may be the first isocenter estimation coordinate.

After that, the distance (d) between the center of gravity coordinate (O1') and the arbitrary isocentric coordinate (O2) indicated by a red circle is calculated, and the calculated value is output in the form of a graph or numerical value by the output unit 153. do.

In an embodiment, the graph output by the output unit 153 may be in the form of a histogram as shown in FIG. 6. That is, when the center of gravity coordinate (O1') shown in FIG. 5 is the first isocentric estimated coordinate, the distance (d) between the center of gravity coordinate (O1') and an arbitrary isocentric coordinate (O2) is displayed on the horizontal axis. And, it is possible to output a graph in the form of dividing the distance d into intervals of a certain size and displaying the number of isocentric coordinates O2 corresponding to each interval on the vertical axis.

In another embodiment, the output unit 153 may output the distance d in the form of a numerical value other than a graph. In this case, the maximum value, the minimum value, the average value, etc. of the distance d may be output as a numerical value, or the distance ( You can also output the range value of d).

Based on the result output as a graph or numerical value by the output unit 153, the determination unit 154 may determine whether the distance between the plurality of isocentric coordinates and the first isocentric estimated coordinate is less than or equal to a preset value. have. For example, when determining based on the graph shown in FIG. 6, it can be seen that the distance d of all the isocentric coordinates O2 shown in FIG. 5 with the center of gravity coordinates O1' corresponds to a preset value of 1 mm or less. have. From these results, it can be evaluated that when the gantry 110 rotates, the first isocenter, which is the rotation center of the gantry 110, does not significantly deviate from the geometric center of the rotation orbit R. Accordingly, it can be concluded that the precision of the rotational movement of the gantry 110 is good.

In addition, the determination unit 154 may determine whether the second isocenter displayed in the center of the first surface S1 of the correction marker unit 124 is aligned with the first isocenter of the gantry 110. Here, the first isocenter of the gantry is the rotational center of the gantry 110, and may be the first isocenter estimated coordinate O1' derived through the above-described process, or may be the geometric center of the rotational trajectory R.

Meanwhile, the second dorsal center corresponds to the location of the patient's affected part on the bed part 126, and is indicated by irradiating the laser beam LB at the center of the first surface S1 as shown in FIG. 1. At this time, the laser beam LB serves to guide the first isocenter of the gantry 110 so that the second isocenter on the bed part 126 can be easily overlapped. Accordingly, the laser beam LB serves to display the reference point of the first coordinate system that defines the real coordinates of the treatment room on the center C0 of the first surface S1, and the first isocenter and the second isocenter are It can also serve as a guide to overlap.

Hereinafter, a method for evaluating a motion of a radiation diagnosis and treatment apparatus performed using the motion evaluation system 10 of the radiation diagnosis and treatment apparatus described above will be sequentially described with reference to FIG. 7.

Referring to FIG. 7, first, a step (S1) of installing a marker unit on the gantry is performed. The marker unit includes at least one marker, and for convenience of explanation, a case where the marker unit includes one marker will be described below.

The gantry has a cylindrical opening in the center. A radiation target may be inserted into the opening, and when the gantry rotates in the circumferential direction of the opening at a constant speed, the radiation may be irradiated to the irradiated body inserted inside the opening.

Thereafter, a step (S2) of photographing the marker is performed by the camera unit. The camera unit may include a plurality of cameras, and each of the plurality of cameras may be disposed to face different positions of the gantry.

In this step (S2), the plurality of cameras generate a marker image by photographing the marker moving on a rotational trajectory when the gantry rotates.

Thereafter, a step (S3) of calculating a plurality of coordinates on a rotation trajectory of the marker is performed based on the marker image. In this step (S3), the three-dimensional coordinates of the marker are calculated based on the CCD information of the plurality of cameras. At this time, various types of motion capture algorithms may be used.

Thereafter, a step (S4) of extracting a plurality of representative coordinates among the plurality of coordinates calculated in the previous step (S3) is performed. In this step (S4), coordinates of positions spaced at a predetermined angle along the circumferential direction of the opening on the rotation orbit may be extracted as the plurality of representative coordinates. At this time, the plurality of representative coordinates extracted may be, for example, 36, whereby the predetermined angle may be 10 degrees.

Thereafter, a step (S5) of selecting a predetermined number of arbitrary coordinates among the plurality of representative coordinates extracted in the previous step (S4) is performed. At this time, at least three coordinates among the plurality of representative coordinates may be selected.

In this step (S5), the isocenter coordinates of the virtual circle passing through the selected at least three arbitrary coordinates are calculated. Here, the isocenter coordinate of the virtual circle means the geometric center of the virtual circle.

Thereafter, the previous step (S5) is performed a plurality of (n) times to obtain a plurality of isocentric coordinates (S6). In this step (S6), the isocentric coordinates of the virtual circle corresponding to the number of all cases are calculated in order to obtain as many isocentric coordinates as possible.

For example, when three arbitrary coordinates are selected among 36 representative coordinates, the isocentric coordinates of the virtual circle passing through the selected arbitrary coordinates may be a total of 14,280, which is a value obtained by calculating 36C3, a combination formula.

In addition, in this step (S6), all the isocentric coordinates of the virtual circle that can be obtained may be displayed on a single coordinate system.

Thereafter, a step (S7) of outputting a distance between the plurality of isocentric coordinates obtained in the previous step (S6) and the first isocentric estimated coordinate is performed. Here, the first isocenter estimation coordinate means a coordinate estimated as the rotation center of the rotation orbit, and in this case, the rotation orbit may have a circular shape that is partially distorted due to deflection and vibration of the gantry.

For example, the first isocenter estimated coordinate may be a center of gravity coordinate calculated by using the plurality of isocenter coordinates as a mass point.

In this step (S7), the distance between each of the plurality of isocentric coordinates and the first isocentric estimated coordinate may be output in the form of a graph or numerical value.

Thereafter, it is determined whether a distance between each of the plurality of isocentric coordinates output in a graph or numerical form and the first isocentric estimated coordinate is less than or equal to a preset value of 1 mm. In this case, when the distances in each of the plurality of isocentric coordinates are all 1 mm or less, it can be evaluated that the first isocenter, which is the rotation center of the gantry, does not significantly deviate from the geometric center of the rotation orbit when the gantry rotates.

Thereafter, a step (S8) of determining whether the second isocenter of the correction marker unit is aligned with the first isocenter of the gantry is performed. Here, the first isocenter of the gantry may be a position of the estimated coordinate of the first isocenter derived through the above-described process, or may be a geometric center of the rotation orbit.

The correction marker part is disposed on a bed part that can be inserted into the opening of the gantry, and a body part having a first surface and a second surface and a plurality of correction markers spaced apart from each other on the first surface of the body part Have them.

Meanwhile, the second isocenter is indicated by irradiating a laser beam to the center of the first surface where the plurality of correction markers are located. In this step (S8), the laser beam serves to guide so that the second isocenter corresponding to the patient's affected area on the bed can be easily superimposed on the first isocenter, which is the rotation center of the gantry.

This makes it possible to pre-evaluate whether the center of rotation of the gantry is aligned with the patient's affected area, so that appropriate measures can be taken to prevent the patient from unnecessarily exposed to radiation.

As described above, the present invention has been described with reference to an embodiment shown in the drawings, but this is only illustrative, and it will be understood by those of ordinary skill in the art that various modifications and variations of the embodiment are possible therefrom. . Therefore, the true technical protection scope of the present invention should be determined by the technical spirit of the appended claims.

Claims

A gantry having a cylindrical opening in the center and rotatable in the circumferential direction of the opening;

A marker unit installed on the gantry and including at least one marker;

A camera unit including a plurality of cameras for photographing the at least one marker;

A coordinate calculator configured to calculate a plurality of coordinates on a rotation trajectory of the at least one marker based on the marker images captured by the plurality of cameras when the gantry rotates; And

A motion evaluation system of a radiation diagnosis and treatment apparatus comprising; an inspection unit for inspecting the positional accuracy of the first isocenter of the gantry using the calculated plurality of coordinates.
The method of claim 1,

The first isocenter is a rotational center of the gantry, a motion evaluation system for a radiation diagnosis and treatment device.
The method of claim 1,

The inspection unit,

A coordinate input unit that receives coordinate values of the plurality of coordinates and extracts a plurality of representative coordinates from among the plurality of coordinates;

Selecting a certain number of arbitrary coordinates among the extracted plurality of representative coordinates to calculate the isocentric coordinates of the virtual circle passing through the selected arbitrary coordinates, and calculating the isocentric coordinates of the virtual circle multiple times An operation unit that obtains the isocentric coordinates of the dogs; And

An output unit for outputting a distance between the obtained plurality of isocentric coordinates and the first isocentric estimated coordinates; comprising, a motion evaluation system of a radiation diagnosis and treatment apparatus.
The method of claim 3,

The plurality of representative coordinates include coordinates of positions spaced at a predetermined angle along the circumferential direction of the opening on the rotational trajectory.
The method of claim 3,

The predetermined number is at least three, the motion evaluation system of the radiation diagnosis and treatment device.
The method of claim 3,

The first isocenter estimation coordinate is a center of gravity coordinate calculated by using the plurality of isocenter coordinates as a material point. A motion evaluation system for a radiation diagnosis and treatment apparatus.
The method of claim 3,

The output unit outputs a distance between each of the plurality of isocentric coordinates and the first isocentric estimated coordinate in the form of a graph or a numerical value, a motion evaluation system of a radiation diagnosis and treatment apparatus.
The method of claim 3,

The inspection unit further includes a determination unit,

The determination unit determines whether a distance between each of the plurality of isocentric coordinates and the first isocentric estimated coordinate is less than or equal to a preset value, a motion evaluation system of a radiation diagnosis and treatment apparatus.
The method of claim 1,

The at least one marker is disposed outside the opening on a surface extending in a direction transverse to the center of the opening of the gantry.
The method of claim 1,

Each of the plurality of cameras is arranged to face a different position of the gantry, a motion evaluation system of a radiation diagnosis and treatment apparatus.
The method of claim 1,

The at least one marker comprises an infrared marker,

The plurality of cameras comprises an infrared camera, the motion evaluation system of the radiation diagnosis and treatment apparatus.
The method of claim 1,

A bed portion disposed to be inserted into the opening; And

Correction comprising a body portion disposed on the bed portion and having a first surface and a second surface opposite to the first surface, and a plurality of correction markers spaced apart from each other on the first surface of the body portion A motion evaluation system of a radiation diagnosis and treatment apparatus further comprising a marker unit.
The method of claim 12,

A first coordinate system defining the real coordinates and the image coordinates are defined using real coordinates of the plurality of correction markers and image coordinates calculated from an image photographed of the plurality of correction markers by the plurality of cameras. Coordinate conversion unit for deriving a conversion relationship between the second coordinate system; further comprising, a motion evaluation system of the radiation diagnosis and treatment apparatus.
The method of claim 13,

A laser oscillation unit that irradiates a laser beam to the center of the first surface to display a second isocenter, which is a reference point of the first coordinate system, further comprising a motion evaluation system of a radiation diagnosis and treatment apparatus.
The method of claim 14,

The inspection unit further includes a determination unit,

The determination unit determines whether the second isocenter of the correction marker unit is aligned with the first isocenter of the gantry. A motion evaluation system for a radiation diagnosis and treatment apparatus.
The method of claim 12,

A motion evaluation system of a radiation diagnosis and treatment device, wherein the second surface faces the gantry.
Installing a marker unit including at least one marker on a gantry having a cylindrical opening at the center and rotatable in a circumferential direction of the opening;

Photographing the at least one marker by a camera unit including a plurality of cameras;

Calculating a plurality of coordinates on a rotation trajectory of the at least one marker based on the marker images captured by the plurality of cameras when the gantry rotates; And

Including, a method for evaluating a motion of a radiation diagnosis and treatment apparatus comprising the step of examining the positional precision of the first isocenter of the gantry using the calculated plurality of coordinates.
The method of claim 17,

The step of checking the positional precision,

Receiving coordinate values of the plurality of coordinates and extracting a plurality of representative coordinates among the plurality of coordinates;

Selecting a predetermined number of arbitrary coordinates from among the extracted plurality of representative coordinates and calculating isocentric coordinates of a virtual circle passing through the selected arbitrary coordinates;

Obtaining a plurality of isocentric coordinates by performing the step of calculating the isocentric coordinates of the virtual circle a plurality of times; And

Outputting a distance between the obtained plurality of isocentric coordinates and the first isocentric estimated coordinate; comprising, a motion evaluation method of a radiation diagnosis and treatment apparatus.
The method of claim 18,

The plurality of representative coordinates include coordinates of positions spaced at a predetermined angle along the circumferential direction of the opening on the rotational trajectory.
The method of claim 18,

The predetermined number is at least three, the motion evaluation method of the radiation diagnosis and treatment device.
The method of claim 18,

The first isocenter estimation coordinate is a center of gravity coordinate calculated by using the plurality of isocenter coordinates as a mass point.
The method of claim 18,

The outputting of the distance comprises outputting a distance between each of the plurality of isocentric coordinates and the first isocentric estimated coordinate in the form of a graph or a numerical value.
The method of claim 18,

The step of checking the positional accuracy comprises determining whether a distance between each of the plurality of isocentric coordinates and the first isocentric estimated coordinate is less than or equal to a preset value, the motion of the radiation diagnosis and treatment apparatus Assessment Methods.
The method of claim 17,

The step of checking the positional accuracy includes determining whether a second isocenter of the correction marker unit disposed on the bed part insertable into the inside of the opening is aligned with the first isocenter of the gantry. , Radiation diagnosis and motion evaluation method of treatment device.
The method of claim 24,

The correction marker portion includes a body portion having a first surface and a second surface opposite to the first surface, and a plurality of correction markers positioned to be spaced apart from each other on the first surface of the body portion,

A method for evaluating motion of a radiation diagnosis and treatment apparatus, wherein the second isocenter is displayed by irradiating a laser beam to the center of the first surface.
The method of claim 25,

The second surface is a method for evaluating motion of a radiation diagnosis and treatment device facing the gantry.