JP2003117009A - Radiotherapy device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem in a conventional radiotherapy device that it is difficult to acquire the three-dimensional coordinates at real time. SOLUTION: This radiotherapy device comprises a CARM linac 15, three tumor markers 17 buried near a tumor, an X-ray fluoroscopic apparatus 21 for picking up images of the tumor markers from the first direction, an X-ray fluoroscopic apparatus 22 for picking up the images of the tumor markers from the second direction, image input parts 26, 28 for digitalizing diorama outputted from the X-ray fluoroscopic apparatuses 21, 22, recognition processing parts 27, 29 for matching template images of the tumor markers to the image information digitalized by the image input parts to determine two-dimensional coordinates of three tumor markers, a central processing part 30 for calculating the three-dimensional coordinates of three tumor markers, an isocentre position and the like on the basis of the two-dimensional coordinates, and an radiation control part 23 for controlling the therapy beam radiation on the basis of the isocentre position and the like. Whereby the radiation of large dosage can be selectively performed to the tumor in a trunk of the body by rotational movement in addition to parallel movement, and the exposure to normal tissue can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention automatically and in real time calculates the position of a tumor that moves around in the trunk without depending on the absolute accuracy of the mechanical system, and selectively increases the size of the tumor. The present invention relates to a radiotherapy apparatus for irradiating radiation such as X-rays, electron beams, proton beams, and heavy particle beams, which can accurately irradiate a dose and reduce exposure to normal tissues.

[0002]

2. Description of the Related Art A conventional radiotherapy apparatus will be described with reference to the drawings. FIG. 16 shows, for example, Japanese Patent Application Laid-Open No.
It is a figure which shows the structure of the conventional radiotherapy apparatus shown by 2074 gazette.

In FIG. 16, 1 is a treatment table, 5 is a patient,
6 and 7 are support rails, and 8 is an X-ray TV camera input device. The X-ray TV camera input device 8 is composed of an X-ray tube 8 a installed on the support rail 6 and an image intensifier 8 b installed on the support rail 7.

Further, in the figure, 9 is a digital image processor connected to the image intensifier 8b, 10 is an electronic computer connected to the digital image processor 9, and 11 is connected to the electronic computer 10.
A treatment table controller connected to the treatment table 1, 12 and 13 are image displays connected to the electronic computer 10, and 14 is a tablet connected to the electronic computer 10.

Next, the operation of the conventional radiotherapy apparatus will be described with reference to the drawings.

FIG. 17 is a view for explaining the positional relationship between the X-ray tube 8a of the conventional radiotherapy apparatus and the affected part S of the patient 5. FIG. 18 is a diagram showing an X-ray TV image of the affected area S.

In FIG. 17, the coordinate axes are the X-axis in the long side direction of the treatment table 1, the Z-axis in the vertical direction, and the Y-axis in the direction perpendicular to the X-axis and the Z-axis. The origin O is defined on the vertical line directly below the center of the treatment table 1 and passing through the X-ray tube 8a at the initial position A. X
Assuming that the height between the line tube 8a and the treatment table 1 is H, the coordinates of the initial position A are (0, 0, H). The intersection point between the vertical axis passing through the position B and the X axis directly below the treatment table 1 is Q. Initial position A of the X-ray tube 8a and initial position B after translation in the X-axis direction
The distance between them is defined as a.

In FIGS. 18 (a) and 18 (b), the values of the affected part S of the patient 5 at the initial position A of the X-ray tube 8a and the position B after translation are represented as S1 and S2, respectively. Patient 5
The coordinate positions of the images S1 and S2 of the affected part S are expressed by a specific point (the center or the periphery of the affected part S).

First, in the initial position A of the X-ray tube 8a,
An X-ray TV image of the affected area S of the patient 5 is captured by the X-ray TV camera input device 8, and the digital image processor 9
After being digitized by, the image distortion correction such as the pincushion distortion is performed and the image is displayed on the image display 12 via the electronic computer 10.

Subsequently, the X-ray tube 8a and the image intensifier 8b are simultaneously moved in parallel on the support rails 6 and 7 in the X-axis direction by a distance a. At the position B after translation, the X-ray TV image of the affected area S of the patient 5 is the X-ray T
The image is captured again by the V camera input device 8 and displayed on the image display 13 via the digital image processor 9 and the electronic computer 10.

Then, the operator uses the tablet 14 to display an image S1 of the affected area S on the image displays 12 and 13.
And S2 are displayed (pointing).

The electronic computer 10 executes the following operations (1) to (4) based on the information of the images S1 and S2 of the supported affected part S. In addition, the vector between the coordinates a and b is "→
a.b ".

(1) The distance l on the X axis between the images S1 and S2 of the affected area S is vector → O.S1 and vector → O.S2
Calculated from the difference between (2) The height h of the affected part S in the Z-axis direction is h = 1 · H / (a
+1). (3) The X, Y, Z coordinates Sx, Sy, Sz of the affected area S are expressed by the following equations when the X, Y coordinate values of the image S1 of the affected area S are X1, Y1 as shown in FIG. Get more. Sx = (1-h / H) * X1 Sy = (1-h / H) * Y1 Sz = h (4) The translation amount of the treatment table 1 is determined by the desired position of the patient 5 and the desired position of the affected part S (Sx , Sy, Sz).

After the above-described arithmetic processing is completed, the treatment table 1 is translated by the treatment table controller 11 in parallel to the desired position in the horizontal and vertical directions based on a command from the electronic computer 10. In this way, the position of the affected part S of the patient 5 can be adjusted to the predetermined three-dimensional coordinate position.

[0015]

In the conventional radiotherapy apparatus as described above, the X-ray TV is used to obtain the three-dimensional coordinates.
It is necessary to move the camera input device (X-ray fluoroscope) each time, and the position where the three-dimensional coordinate is desired to be calculated must be manually specified each time.
There is a problem that it depends on the mechanical accuracy of the line TV camera input device attachment and the absolute position of the patient, and it is difficult to apply to real-time three-dimensional coordinate acquisition.

Further, since another conventional positioning apparatus is intended to correct only the isocenter position by measuring the marker positions on a plurality of body surfaces, when there is rotational movement of the tumorous part in the body, There is a problem that an appropriate irradiation field cannot be obtained, and since the marker placed on the body surface is used, the position of the tumor in the body can be obtained only indirectly. In particular, when a tumor in the body moves around during treatment, the body surface marker has a problem that it is difficult to correct it because a time lag occurs with respect to the movement of the tumor part.

The present invention has been made to solve the above-mentioned problems, and automatically calculates the position of a tumor moving around in the trunk and the irradiation field to be set for the tumor in real time. An object of the present invention is to obtain a radiotherapy device capable of ensuring a substantially required accuracy without depending on the absolute accuracy of the mechanism system.

It is another object of the present invention to provide a radiation treatment apparatus capable of selectively irradiating a large dose accurately and reducing exposure to normal tissue.

[0019]

A radiotherapy apparatus according to the present invention comprises a CARM linac for irradiating a tumor with a treatment beam, at least three tumor markers embedded in the vicinity of the tumor, and the tumor marker as a first object. And a second X-ray apparatus that simultaneously images the tumor marker from the second direction at the same time as the first X-ray fluoroscopic apparatus.
The fluoroscopic apparatus, the 1st and 2nd image input parts which digitize the 1st and 2nd fluoroscopic images output from the 1st and 2nd X-ray fluoroscopic apparatuses, respectively, and the 1st and 2nd The template matching by the grayscale normalization cross-correlation method in which the template image of the tumor marker registered in advance is applied to the image information digitized by the image input unit of FIG. The first and second two-dimensional coordinates of the marker are respectively converted into first and second recognition processing units to be obtained, and first and second two-dimensional coordinates calculated by the first and second recognition processing units. A three-dimensional coordinate of the three tumor markers, and a central processing unit for calculating an isocenter position, a treatment beam direction, and an irradiation field shape obtained from the three-dimensional coordinates of these tumor markers; Obtained from three-dimensional coordinates of the tumor marker obtained isocenter position, in which a treatment beam direction, and the irradiation controller for controlling the treatment beam irradiation of the CARM linac by irradiation field shape.

Further, the radiotherapy apparatus according to the present invention is
Drive control of each drive axis of the CARM linac based on the correction amount of each drive axis of the CARM linac obtained from the isocenter position calculated by the three-dimensional coordinates of the tumor marker, the treatment beam direction, and the irradiation field shape. Each drive axis drive control unit is further provided, and the treatment control beam is tracked and irradiated by the irradiation control unit while the position of the tumor moving in the trunk is corrected in real time by each drive shaft drive control unit.

Further, the radiotherapy apparatus according to the present invention is
A predetermined drive amount for each drive axis to be controlled is a correction amount of each drive axis of the CARM linac obtained from the isocenter position calculated by the three-dimensional coordinates of the tumor marker, the treatment beam direction, and the irradiation field shape. When it exceeds the possible range, it further comprises a drive range determination section for stopping the operation of each drive axis drive control section and the irradiation control section.

Further, in the radiotherapy apparatus according to the present invention, when the isocenter position calculated by the three-dimensional coordinates of the tumor marker, the treatment beam direction, and the irradiation field shape exceed a predetermined trackable range, It further comprises a drive range drive control section and a tracking range determination section for stopping the operation of the irradiation control section.

The radiotherapy device according to the present invention is a CARM linac for irradiating a tumor with a treatment beam, at least three tumor markers embedded in the vicinity of the tumor, and a first image capturing the tumor marker from a first direction. 1 fluoroscope and the tumor marker from a second direction to the first X-ray
A second X-ray fluoroscopy device that images simultaneously with the fluoroscopy device, and first and second digitizing first and second fluoroscopic images output from the first and second X-ray fluoroscopy devices, respectively.
Image input section and template matching by the grayscale normalization cross-correlation method in which a template image of a tumor marker registered in advance is applied to the image information digitized by the first and second image input sections at a predetermined frame rate. Run at real-time level, the first of the three tumor markers
And the second two-dimensional coordinates are first and second obtained, respectively.
Recognition processing unit, the three-dimensional coordinates of the three tumor markers based on the first and second two-dimensional coordinates calculated by the first and second recognition processing units, and three of these tumor markers. A central processing unit that calculates the isocenter position, the treatment beam direction, and the irradiation field shape obtained from the three-dimensional coordinates is obtained, and the three-dimensional coordinates of the tumor marker are acquired at least once immediately before the treatment, and calculated by these coordinates. The drive axes of the CARM linac are aligned before treatment based on the correction amount of each drive axis obtained from the isocenter position, the treatment beam direction, and the irradiation field shape.

Further, the radiotherapy apparatus according to the present invention is
Using four or more tumor markers, the central processing unit statistically processes four or more tumor marker coordinates to increase the accuracy of the calculated isocenter position, treatment beam direction, and irradiation field shape. It has a statistical processing function.

Further, the radiation therapy apparatus according to the present invention is
A normal linac is provided instead of the CARM linac.

Furthermore, in the radiotherapy apparatus according to the present invention, the central processing unit has a corrected gantry angle of 0.
Gantry angle of 0 when deg is around 180 deg
Set the allowable value for deg or 180 deg,
If the amount of deviation is less than or equal to the allowable value, set the gantry angle to 0 de
The calculation is performed by regarding it as g or 180 deg.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. A radiotherapy apparatus according to Embodiment 1 of the present invention will be described with reference to the drawings. 1 is a diagram showing a configuration of a radiation therapy apparatus according to Embodiment 1 of the present invention. In each figure, the same reference numerals indicate the same or corresponding parts.

In FIG. 1, reference numeral 15 is a CARM linac, 16 is a treatment beam irradiated from the CARM linac 15, and 17a, 17b and 17c are Au, Pt having a diameter of about 1 to 2 mm or implanted in a tumor in a patient. A spherical tumor marker made of a material such as Ir that is less harmful to the human body and has a large absorption of X-rays, 18 is a tumor in the body,
Reference numeral 19 is a patient, and 20 is a treatment table provided with a top plate made of a material such as CFRP which has a low X-ray absorption.

In the figure, 21a is an X-ray tube A installed under the floor of the treatment room, 21b is a collimator A for narrowing the X-rays emitted from the X-ray tube A (21a), and 21c is an X-ray tube. The X-rays A and 21d emitted from A (21a) are image intensifiers A and 21e installed on the ceiling of the treatment room, which is diagonally opposite to the X-ray tube A (21a), with the isocenter in between. (21
The TV cameras A and 21f connected to the d) are connected to the X-ray tube A (2
1a) is an X-ray high voltage device A. In addition, the X-ray fluoroscope A (21) includes the X-ray tubes A (21a) to X described above.
The line high voltage device A (21f) is used.

In the figure, 22a is an X-ray tube B installed under the floor of the treatment room, 22b is a collimator B for narrowing the X-rays emitted from the X-ray tube B (22a), and 22c is an X-ray tube. The X-rays B and 22d emitted from B (22a) are image intensifiers B and 22e installed on the ceiling of the treatment room, which is diagonally across the X-ray tube B (22a), with the isocenter in between. (22
The TV camera B, 22f connected to the d) is an X-ray tube B (2
2a) is an X-ray high-voltage device B for controlling. The X-ray fluoroscope B (22) is composed of the X-ray tube B (22a) to the X-ray high voltage device B (22f).

Further, in the figure, 23 is an irradiation control section for directly turning on / off the treatment beam 16 of the CARM linac 15, and 24 is a camera control unit (C
CU) A, 25 are camera control units (CC
U) B, 26 is an image input unit A, 27 is a recognition processing unit A, 2
8 is an image input unit B, 29 is a recognition processing unit B, 30 is a central processing unit, 31 is a trigger control unit, 32 is an image display unit, 3
3 is a monitor.

Next, the operation of the radiotherapy apparatus according to the first embodiment will be described with reference to the drawings.

2 and 3 show the first embodiment of the present invention.
It is a figure which shows the perspective image of the radiotherapy apparatus which concerns on.

First, based on an instruction from the central processing unit 30, the X-ray high voltage apparatus A (21
f), the X-ray irradiation permission signal is applied to the X-ray high voltage device B (22f), and the X-ray tube A (21a) and the X-ray tube B
X-rays are emitted from (22a).

At the same time, a synchronization signal is sent from the trigger control section 31 to the camera control unit A (24), the camera control unit B (25), the image input section A (26) and the image input section B (28). , TV camera A
The images of (21e) and the TV camera B (22e) are sent to the recognition processing unit A (27) and the recognition processing unit B (29) in synchronization with each other at a constant cycle.

X-ray A emitted from X-ray tube A (21a)
(21c) shows tumor markers 17a, 1 embedded in the vicinity of the tumor 18 in the body of the patient 19 on the CFRP treatment table 20.
As shown in FIG. 2 (a), on the tube surface of the image intensifier A (21d) passing near 7b and 17c,
A perspective image A is formed.

This perspective image A is a TV camera A (21e).
Is converted into an electric signal by the camera control unit A (24) and is input to the image input unit A (26). As shown in FIG. 2C, the resolution is about 1024 × 1024, and about 256 steps per pixel. It is sent to the recognition processing unit A (27) after being digitized to the gradation of.

In the recognition processing section A (27), the processing shown in FIG.
Pre-stored tumor marker 1 shown in (b)
Template matching is performed between the template image A, which is the reference image of 7a, 17b, and 17c, and the digitized perspective image A shown in FIG. Then, the tumor marker coordinate A having the highest correlation on the digitized fluoroscopic image A
And sends the result to the central processing unit 30.

Similarly, the X-ray B (22c) emitted from the X-ray tube B (22a) passes through the vicinity of the tumor marker 17 embedded in the vicinity of the tumor 18 inside the body of the patient 19 on the treatment table 20, and is imaged. A perspective image B as shown in FIG. 3A is formed on the tube surface of the intensifier B (22d).

This perspective image B is a TV camera B (22e).
Is converted into an electric signal by the camera control unit B (25) and input to the image input unit B (28). As shown in FIG. 3C, the resolution is about 1024 × 1024, and about 256 steps per pixel. It is digitized to the gradation of and sent to the recognition processing unit B (29).

In the recognition processing section B (29), as shown in FIG.
Pre-stored tumor marker 1 shown in (b)
Template matching is performed between the template image B, which is the reference image of 7a, 17b, and 17c, and the digitized perspective image B shown in FIG. Then, the tumor marker coordinate B having the highest correlation on the digitized fluoroscopic image B
And sends the result to the central processing unit 30.

Note that the template matching method based on the grayscale normalized cross-correlation performs an inspection by performing the following equation between a reference image (template) registered in advance and an image in which a marker is (probably) present. The degree of presence of the marker in the image is obtained.

[0043]

[Equation 1]

Actually, the correlation value Qx between the template image Gi and the search image (perspective image after digitization) Fi is shifted while sequentially shifting the local area Sx, y having the same size as the template starting from the coordinates (x, y). y is calculated, and it is determined whether or not an object equivalent to the template exists at the coordinate (x, y) based on the obtained correlation value.

The tumor markers 17a, 17b and 1
7c is made of a material such as Au, Pt, and Ir that is harmless to the human body and is opaque to X-rays, and can be highly discriminated even in complicated perspective images such as organs and bones. The shapes of the tumor markers 17a, 17b, and 17c are
It has a spherical shape with a diameter of 1 to 2 mm, and has the effect of being spherically recorded on a fluoroscopic image regardless of how it is placed in the body or from which direction the fluoroscopy is performed. This means that in the general template matching method, when the recognition target changes its shape in the search image due to rotation etc., a plurality of templates corresponding to various angles are sequentially tried, and the operation to obtain the highest recognition degree is performed. On the other hand, it has a great effect on reducing the processing speed in that a complete result can be obtained by one trial.

Next, in the central processing unit 30, the tumor marker coordinates Aa, Ab, and Ac are calculated by the pre-stored perspective transformation matrix M _A of the perspective system A in the vicinity of the isocenter of the tumor markers 17a, 17b, and 17c.
Is transformed into a linear equation that is believed to exist on it.

Similarly, in the central processing unit 30, the tumor marker coordinates Ba, Bb, and Bc are calculated in accordance with the perspective transformation matrix M _B of the perspective system B stored in advance in the tumor markers 17a, 17b, and 17 near the isocenter.
c is transformed into a linear equation which is considered to exist on it.

Further, the central processing unit 30 obtains the three-dimensional coordinates of the tumor markers 17a, 17b, and 17c by finding the intersection of the equations of the two straight lines thus obtained.

The central processing unit 30 obtains the initially planned isocenter position, the treatment beam direction, and the deviation amount of the irradiation field shape from the three-dimensional coordinates of the obtained three tumor markers, and calculates these. Six correction amounts for normalization, namely, treatment table LONG axis coordinates, treatment table LAT axis coordinates, treatment table VERT axis coordinates, gantry angle, CARM angle,
And calculate the collimator angle.

When each of the isocenter position, the treatment beam direction, and the deviation amount of the irradiation field shape is within a given range, the central processing unit 30 sends a treatment beam enable signal to the irradiation control unit 23. Send out,
The irradiation control unit 23 instructs the CARM linac 15 to irradiate the treatment beam 16.

On the contrary, the obtained tumor markers 17a, 17a
If the isocenter position, the treatment beam direction, and the deviation amount of the irradiation field shape calculated by the comparison calculation of the three-dimensional coordinates of b and 17c are not within the predetermined allowable ranges, the irradiation control unit 23 is treated. The beam enable signal is not transmitted, and the irradiation control unit 23 instructs the CARM linac 15 to interrupt the treatment beam irradiation.

In this way, the tumor markers 17a, 17
The treatment beam 16 by the CARM linac 15 is provided only when the isocenter position, the treatment beam direction, and the deviation amount of the irradiation field shape calculated by the comparison calculation of the three-dimensional coordinates of b and 17c are within the predetermined allowable range. Will be irradiated.

The perspective transformation matrix M required by the central processing unit 30 is obtained as follows.

FIG. 4 is a diagram showing a spatial coordinate calibrator used in the radiotherapy apparatus according to the first embodiment.

As shown in FIG. 4 (a), the spatial coordinate calibrator 40 has an A mark near the apex of a cube made of a material relatively transparent to X-rays such as acrylic and having a side length of 40 to 80 mm.
Diameter 1 opaque to X-rays such as u, W, or Pb
Spherical substances (markers) M1 to M8 having a size of about 2 mm are accurately embedded so as to be located at fixed positions from the respective vertices, and marking lines are provided between the midpoints of opposite sides on each surface.

FIGS. 5 and 6 are views showing a perspective path through which the X-ray passes through the spatial coordinate calibrator 40 by the fluoroscope.

In FIG. 6, for example, (a) is a perspective path 1 passing from the mark M5 to the mark M3 of the spatial coordinate calibrator 40.
The perspective image of the spatial coordinate calibrator 40 centering on is shown. Similarly, (b) to (d) show perspective passes 2 to 4.

First, the spatial coordinate calibrator 40 is placed on the treatment table 20, and with the marking lines on each surface of the spatial coordinate calibrator 40 as a guide, the spatial coordinate calibrator is used by using the laser pointer used for treatment positioning. Positioning is performed so that the center of 40 becomes the isocenter.

Next, according to an instruction from the central processing unit 30,
The X-ray irradiation permission signal is applied from the trigger control unit 31 to the X-ray high voltage device A (21f), and the X-ray tube A (21a)
Image intensifier A irradiated with more X-rays
A perspective image A of the spatial coordinate calibrator 40 is formed on (21d).

This perspective image A is a TV camera A (21e).
Is converted into an electric signal by the camera control unit A (24), digitized by the image input unit A (26), taken into the central processing unit 30, and displayed on the monitor 33 by the image display unit 32.

The operator associates the positions on the perspective image of 6 points of the perspective image of the 8 vertices (markers) of the spatial coordinate calibrator 40 displayed on the monitor 33 with the actual coordinates from each isocenter. The central processing unit 30 is instructed.

The central processing unit 30 obtains the coordinates (x _{A i} , y _{A i} ) | i = 1,6 on the fluoroscopic image of the tumor marker 17 by designating the position on the fluoroscopic image and gives them in association with each other. The three-dimensional coordinates (X _{A i} , Y _{A i} , Z _{A i} ) | i = 1, 6 with the obtained isocenter as the origin are obtained, and the perspective transformation matrix M _A in the projective geometry of the perspective system _A is calculated.

This perspective transformation matrix M _A is the tumor marker 17
The homogeneous coordinates [a _A ] with respect to the real coordinates in the three-dimensional space of
Assuming that the coordinates on the perspective image are homogeneous coordinates [b _A ], [a _A M _A ] = by a matrix M _A of 4 × 3, rank3
It can be represented as [b _A ]. In order to obtain the matrix M _A in general, it is necessary to obtain the combination information of 6 points [a] and [b], which is the reason why the 6 vertex coordinates of the spatial coordinate calibrator 40 are used.

Similarly, in accordance with an instruction from the central processing unit 30, the X-ray high voltage device B (22) from the trigger control unit 31.
The X-ray irradiation permission signal is applied to f), and the X-ray tube B
X-rays are emitted from (22a), and a perspective image B of the spatial coordinate calibrator 40 is displayed on the image intensifier B (22d).
Image.

This perspective image B is a TV camera B (22e).
Is converted into an electric signal by the camera control unit B (25), digitized by the image input unit B (28), taken into the central processing unit 30, and displayed on the monitor 33 by the image display unit 32.

The operator associates the positions on the perspective image of 6 points of the perspective image of the 8 vertices of the spatial coordinate calibrator 40 displayed on the monitor 33 with the actual coordinates from the respective isocenters, and performs central arithmetic processing. Instruct the unit 30.

The central processing unit 30 determines the position on the perspective image.
By the designation of tumor markers 17a, 17b, and 17c
Coordinates (x_{B i}, Y_{B i}) | I = 1,6
In both cases, the isocenter given in association with each other was used as the origin.
Three-dimensional coordinates (X_{B i}, Y_{B i}, Z _{B i}) | I = 1,6 is obtained,
Perspective transformation matrix M in projective geometry in perspective system B _B
To calculate.

This perspective transformation matrix M _B is the tumor marker 17
Let a homogeneous coordinate [a _B ] of a, 17 b, and 17 c in the three-dimensional space and a homogeneous coordinate [b _B ] of the coordinates in the perspective image. 4 × 3, rank3 matrix M _B
Can be expressed as [a _B M _B ] = [b _B ].

When the perspective transformation matrix M is determined and the coordinates of the points on the perspective image are determined, a coordinate group (linear equation) in which corresponding points can exist in the three-dimensional space is determined by the above conversion formula. Therefore, from the perspective image A and the perspective image B obtained by seeing through the three tumor markers 17a, 17b, and 17c with the perspective system A and the perspective system B, respectively, three sets of two markers passing through the three tumor marker coordinates in the space are displayed. The equation of two straight lines is obtained, and three tumor markers
The three-dimensional coordinates of a, 17b, and 17c can be obtained.

The three individual markers are identified based on the continuity of the images, and the consistency is determined by the position information obtained from the corresponding other fluoroscopic image.

The isocenter position, the treatment beam direction, and the irradiation field shape are calculated as follows from the spatial coordinates of the three-point marker. At this time, it is treated as the treatment room coordinate system {A} and the CT coordinate system {B}.

First, three markers P, Q and R are defined, and a marker frame {C} composed of them is defined as follows. As shown in FIG. 7, two vectors (→) QP,
The (→) QR is as follows.

[0073]

[Equation 2]

Next, the tumor frame {D} is defined as shown in FIG. The relationship between the treatment room coordinate system and the tumor frame is CA
In the case of the RM linac 15, only the rotation amount is shown as follows. That is, the gantry angle φ, the CARM angle ξ, and the collimator angle θ are as follows.

[0075]

[Equation 3]

[0076] That is, when ^A _D R is known, the corresponding gantry angle phi, it is possible to obtain the CARM angle xi], the collimator angle theta.

Posture after rotational displacement of the tumor frame^A _{D '}T
Is^A _DA parallel movement is added to R, and
Marker frame after rolling displacement^A _{C '}If you know T,
Can be calculated.^A _{C '}T is the actual measurement of the three-point marker
The pose of the planning marker frame, obtained by^A _CCorresponds with T
By doing so, the rotational displacement amount can be obtained.
^A _{D '}Once T is obtained, the corresponding gantry angle φ ', I
It is possible to obtain the ROT angle ψ ′ and the collimator angle θ ′.
Become.

First, the plan marker frame {C} is CT
It is defined according to the coordinate system {B}. That is,

[0079]

[Equation 4]

Therefore,

[0081]

[Equation 5]

It is Next, the measured marker frame {C ′} is obtained according to the treatment room coordinate system {A}.

[0083]

[Equation 6]

By these,

[0085]

[Equation 7]

It becomes possible to calculate as follows.

Embodiment 2. (Tracking irradiation) A radiotherapy apparatus according to Embodiment 2 of the present invention will be described with reference to the drawings. FIG. 9 is a diagram showing the configuration of the radiation treatment apparatus according to the second embodiment of the present invention.

In the first embodiment, when each of the isocenter position, the treatment beam direction, and the deviation amount of the irradiation field shape is within a predetermined range, the central processing unit 30 instructs the irradiation control unit 23 to do so. And transmits the treatment beam enable signal, and the irradiation control unit 23 instructs the CARM linac 15 to irradiate the treatment beam 16.

In the second embodiment, each drive axis drive control unit 34 controls each drive axis (treatment table LONG axis, treatment table LAT) so as to cancel the deviation amount of the isocenter position, the treatment beam direction, and the irradiation field shape. Axis, treatment table VERT axis,
By controlling the positions of the gantry angle, the CARM angle, and the collimator angle), it is possible to continue highly accurate treatment without stopping the treatment beam 16 even if the tumor moves around in the body.

At this time, in the CARM linac 15,
It is characterized in that it is possible to continuously and smoothly correct fluctuations in the treatment beam direction by biaxial driving of the gantry angle and the CARM angle.

Third Embodiment (Limitation of Driving Range) A radiotherapy apparatus according to Embodiment 3 of the present invention will be described with reference to the drawings. FIG. 10 is a diagram showing the configuration of the radiation therapy apparatus according to the third embodiment of the present invention.

In the second embodiment, each drive axis drive control unit 34 controls each drive axis (treatment table LONG axis, treatment table LAT) so as to cancel the deviation amount of the isocenter position, the treatment beam direction, and the irradiation field shape. Axis, treatment table VERT axis,
Although the position control of the gantry angle, CARM angle, and collimator angle) is performed, the drive range of each axis is limited in the third embodiment.

That is, the drivable range is set in advance for each drive axis, and the drive range determination unit 35 temporarily drives each drive axis drive control when a correction amount exceeding the drivable range is required. The drive axis correction by the unit 34 and the irradiation of the treatment beam 16 by the irradiation control unit 23 are stopped, and when the correction can be performed within the drivable range, the irradiation of the treatment beam 16 is automatically restarted.

This has the effect of preventing the drive shafts from interfering with each other.

Fourth Embodiment (Limitation of Tracking Range) A radiotherapy apparatus analog according to Embodiment 4 of the present invention will be described with reference to the drawings. FIG. 11 is a diagram showing the configuration of the radiotherapy apparatus according to the fourth embodiment of the present invention.

In the second embodiment, each drive axis drive controller 34 controls each drive axis (treatment table LONG axis, treatment table LAT) so as to cancel out the deviation amount of the isocenter position, the treatment beam direction, and the irradiation field shape. Axis, treatment table VERT axis,
The position control of the gantry angle, the CARM angle, and the collimator angle) is performed, but in the fourth embodiment, the allowable range (tracking range) of the deviation amount of the isocenter position, the treatment beam direction, and the irradiation field shape is limited. Is.

That is, the tracking range is set in advance for each of the isocenter position, the treatment beam direction, and the deviation amount of the irradiation field shape, and the tracking range determination unit 36 needs a correction amount that exceeds the tracking range. In this case, when the driving axis correction by each driving axis drive control unit 34 and the irradiation of the treatment beam by the irradiation control unit 23 are temporarily stopped and the correction can be performed within the trackable range, the irradiation of the treatment beam is performed. To restart automatically.

As a result, for example, even when the treatment beam direction is largely deviated, it is possible to prevent a large variation in the dose distribution of the tumor part due to a change in body thickness or the like in an attempt to forcibly correct the deviation. is there.

Embodiment 5. (Positioning Function) A radiotherapy apparatus according to Embodiment 5 of the present invention will be described with reference to the drawings. FIG. 12 is a diagram showing the configuration of the radiation treatment apparatus according to the fifth embodiment of the present invention.

In each of the above-described embodiments, the movement of the tumor during treatment is captured, and intermittent irradiation or tracking irradiation is performed as necessary. In this fifth embodiment, pre-treatment positioning is performed. Is what you use.

That is, in the treatment of a tumor having almost no movement, it is not necessary to constantly monitor it during the treatment, and the positioning by the three-point marker is effective in terms of confirming the position before the treatment. Even in this case, the CARM linac 15 is still suitable for correcting the deviation amount of the isocenter position, the treatment beam direction, and the irradiation field shape.

This eliminates the need for the irradiation control section 23 and each drive axis drive control section 34, and has the effect of making it easier to reduce the size and cost of the device.

Sixth Embodiment (Use of 4 or More Markers) A radiotherapy apparatus according to Embodiment 6 of the present invention will be described with reference to the drawings. FIG. 13 is a diagram showing the configuration of the radiation therapy apparatus according to the sixth embodiment of the present invention.

In the first embodiment and other embodiments, the number of tumor markers 17 used is three, but in the sixth embodiment, four or more tumor markers 17 are used. .

At least three tumor markers are required to obtain the translation amount and rotation amount of the tumor in the body, but by using four or more tumor markers, the statistical processing function 30a of the central processing unit 30 can use the markers. The coordinates can be statistically processed, and there is an effect that the accuracy of the deviation amount of the isocenter position, the treatment beam direction, and the irradiation field shape calculated from these coordinates is increased.

Seventh Embodiment (Normal Correction with Linac) A radiotherapy apparatus according to Embodiment 7 of the present invention will be described with reference to the drawings. FIG. 14 is a diagram showing the configuration of the radiation therapy apparatus according to the second embodiment of the present invention.

Although the CARM linac 15 is used as the treatment device in the first embodiment and the other embodiments, in the seventh embodiment, the normal linac 15 is used.
A is used.

In the case of the normal linac 15A, it is possible to output the amount of rotation of the gantry, IROT, and collimator as the rotation correction axis for correction, but when the gantry angle is 0 or π, the IROT angle and collimator are The angle solution is only the phase difference, and the IROT is near the gantry angle of 0 and π.
There is a problem that the solution of the angle and the collimator angle is greatly affected by the error and becomes unstable. However, except this point, CARM
The same effect as the linac 15 can be obtained.

In the case of the normal linac 15A, the isocenter position, the treatment beam direction, and the irradiation field shape are calculated as follows from the spatial coordinates of the three-point marker. At this time,
Treated as the treatment room coordinate system {A} and the CT coordinate system {B}.

First, the three markers are P, Q, and R, and the marker frame {C} composed of them is defined as follows. As shown in FIG. 7, two vectors (→) QP,
The (→) QR is as follows.

[0111]

[Equation 8]

Next, the tumor frame {D} is defined as shown in FIG.

In the case of the normal linac 15A, the relationship between the treatment room coordinate system and the tumor frame is as follows if only the rotation amount is shown. That is, the gantry angle φ, the IROT angle ψ, and the collimator angle θ are as follows.

[0114]

[Equation 9]

[0115] That is, when ^A _D R is known, the corresponding gantry angle phi, it is possible to obtain the IROT angle [psi, the collimator angle theta.

Posture after rotational displacement of the tumor frame^A _{D '}T
Is^A _DA parallel movement is added to R, and
Marker frame after rolling displacement^A _{C '}If you know T,
Can be calculated.^A _{C '}T is the actual measurement of the three-point marker
The pose of the planning marker frame, obtained by^A _CCorresponds with T
By doing so, the rotational displacement amount can be obtained.
^A _{D '}Once T is obtained, the corresponding gantry angle φ ', I
It is possible to obtain the ROT angle ψ ′ and the collimator angle θ ′.
Become.

First, the plan marker frame {C} is CT
It is defined according to the coordinate system {B}. That is,

[0118]

[Equation 10]

Therefore,

[0120]

[Equation 11]

It is Next, the measured marker frame {C ′} is obtained according to the treatment room coordinate system {A}.

[0122]

[Equation 12]

By these,

[0124]

[Equation 13]

It is possible to calculate as follows.

Eighth Embodiment (The gantry angle is 0 deg,
Processing in the case of around 180 deg.) A radiotherapy apparatus according to Embodiment 8 of the present invention will be described with reference to the drawings. FIG. 13 is a diagram showing the processing contents of the radiotherapy apparatus according to the eighth embodiment of the present invention.

In the seventh embodiment, the case where the normal linac 15A is used has been described. However, when the gantry angle is near 0 deg and 180 deg, the IROT angle greatly changes with respect to a slight change in the treatment beam direction. There is a case.

For example, when the treatment beam direction was the Z-axis direction in the treatment room coordinate system at the time of planning, but was slightly rotated around the X-axis at the time of actual measurement, the fluctuation amount of the IROT angle reached 90 deg and the treatment was performed. Can be difficult. In such a case, the gantry angle is 0 deg or 180 deg
If the amount of deviation is less than the allowable value, the gantry angle is set to 0 deg or 180d.
The calculation is performed by the central processing unit 30 by regarding it as an egg.

By thus performing the rounding process for the specific gantry angle, unnecessary operation of the treatment table 20 can be prevented.

[0130]

As described above, the radiation treatment apparatus according to the present invention is a CARM for irradiating a tumor with a treatment beam.
A linac, at least three tumor markers embedded in the vicinity of the tumor, a first fluoroscope for imaging the tumor marker from a first direction, and a second tumor marker
A second X-ray fluoroscopic apparatus that simultaneously captures images from the first X-ray fluoroscopic apparatus in the direction of, and first and second fluoroscopic images output from the first and second X-ray fluoroscopic apparatuses, respectively. By the grayscale-normalized cross-correlation method in which the first and second image input sections to be digitized and the template image of the tumor marker registered in advance are applied to the image information digitized by the first and second image input sections Template matching is performed at a real-time level of a predetermined frame rate to obtain first and second two-dimensional coordinates of the three tumor markers, respectively, first and second recognition processing units, and the first and second recognition processing units. The three-dimensional coordinates of the three tumor markers based on the first and second two-dimensional coordinates calculated by the second recognition processing unit, and the isocenter position and treatment obtained from the three-dimensional coordinates of these tumor markers A central processing unit for calculating the beam direction and irradiation field shape, and controlling the treatment beam irradiation of the CARM linac according to the isocenter position, the treatment beam direction, and the irradiation field shape obtained from the obtained three-dimensional coordinates of the tumor marker. Since it is provided with an irradiation control unit for performing irradiation, a large dose of irradiation is selectively applied to a tumor in the trunk including translational movement as well as translational movement, and it is possible to reduce exposure to normal tissue.

Further, the radiotherapy apparatus according to the present invention is
As described above, each drive of the CARM linac is based on the correction amount of each drive axis of the CARM linac obtained from the isocenter position calculated by the three-dimensional coordinates of the tumor marker, the treatment beam direction, and the irradiation field shape. Each drive axis drive control unit for driving and controlling the axis is further provided, and while performing the real-time position correction for the tumor moving around in the trunk by each drive axis drive control unit, the irradiation control unit performs tracking irradiation with the treatment beam. Therefore, even if the tumor moves around in the trunk, the treatment with high accuracy can be continued without stopping the treatment beam.

Further, as described above, the radiotherapy apparatus according to the present invention includes each of the CARM linacs obtained from the isocenter position calculated by the three-dimensional coordinates of the tumor marker, the treatment beam direction, and the irradiation field shape. When the correction amount of the drive axis exceeds the drivable range determined in advance for each drive axis to be controlled, each drive axis drive control section and a drive range determination section for stopping the operation of the irradiation control section are further provided. Since it is provided, it is possible to prevent the drive shafts from interfering with each other.

Furthermore, as described above, the radiotherapy apparatus according to the present invention has a trackable range in which the isocenter position, the treatment beam direction, and the irradiation field shape calculated by the three-dimensional coordinates of the tumor marker are predetermined. If it exceeds the above range, the drive range drive control section and the tracking range determination section for stopping the operation of the irradiation control section are further provided, and thus the tumor is displaced so much that the difference in dose distribution cannot be ignored. The effect that it is possible to prevent the continuation of treatment depending on the condition is exhibited.

As described above, the radiation treatment apparatus according to the present invention includes a CARM linac for irradiating a tumor with a treatment beam, and at least three CARM linacs embedded near the tumor.
A second tumor radiographing device, a first X-ray fluoroscope that images the tumor marker from a first direction, and a second radiograph that simultaneously images the tumor marker from a second direction with the first fluoroscope.
X-ray fluoroscopic device, first and second image input units for digitizing first and second fluoroscopic images output from the first and second X-ray fluoroscopic devices, respectively, and the first and second The template matching by the density normalization cross-correlation method in which the template image of the tumor marker registered in advance is applied to the image information digitized by the second image input unit is executed at a real-time level of a predetermined frame rate,
First and second recognition processing units for obtaining first and second two-dimensional coordinates of each tumor marker, and first and second two calculated by the first and second recognition processing units. A three-dimensional coordinate of the three tumor markers based on three-dimensional coordinates, and a central processing unit that calculates an isocenter position, a treatment beam direction, and an irradiation field shape obtained from the three-dimensional coordinates of these tumor markers, Before the treatment, the three-dimensional coordinate of the tumor marker is acquired at least once immediately before the treatment, and based on the correction amount of each drive axis obtained from the isocenter position, the treatment beam direction, and the irradiation field shape calculated by the coordinate. Since the drive shafts of the CARM linac are aligned with each other, it is possible to reduce the size and cost of the device.

Further, the radiation therapy apparatus according to the present invention is
As described above, four or more tumor markers are used, and the central processing unit statistically processes four or more tumor marker coordinates to calculate the calculated isocenter position, treatment beam direction, and irradiation field shape. Since it has a statistical processing function for increasing the certainty, it is possible to increase the accuracy of the deviation amount of the isocenter position, the treatment beam direction, and the irradiation field shape.

Further, as described above, the radiation treatment apparatus according to the present invention has the same effect even if the normal linac is provided instead of the CARM linac.

Furthermore, in the radiotherapy apparatus according to the present invention, the central processing unit has a corrected gantry angle of 0.
Gantry angle of 0 when deg is around 180 deg
Set the allowable value for deg or 180 deg,
If the amount of deviation is less than or equal to the allowable value, set the gantry angle to 0 de
Since it is calculated as g or 180 deg, it is possible to prevent unnecessary operation of the treatment table.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a radiotherapy apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a perspective image of the radiotherapy apparatus according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a perspective image of the radiotherapy apparatus according to the first embodiment of the present invention.

FIG. 4 is a diagram showing a spatial coordinate calibrator used in the positioning method for the radiation treatment apparatus according to the first embodiment of the present invention.

FIG. 5 is a diagram showing a perspective path of a spatial coordinate calibrator used in the positioning method for the radiotherapy apparatus according to the first embodiment of the present invention.

FIG. 6 is a diagram showing a perspective path of a spatial coordinate calibrator used in the method of positioning the radiotherapy apparatus according to the first embodiment of the present invention.

FIG. 7 is a diagram showing a marker frame of the radiotherapy apparatus according to the first embodiment of the present invention.

FIG. 8 is a diagram showing a tumor frame of the radiotherapy apparatus according to the first embodiment of the present invention.

FIG. 9 is a diagram showing a configuration of a radiotherapy apparatus according to a second embodiment of the present invention.

FIG. 10 is a diagram showing a configuration of a radiotherapy apparatus according to a third embodiment of the present invention.

FIG. 11 is a diagram showing a configuration of a radiotherapy apparatus according to a fourth embodiment of the present invention.

FIG. 12 is a diagram showing a configuration of a radiotherapy apparatus according to a fifth embodiment of the present invention.

FIG. 13 is a diagram showing a configuration of a radiotherapy apparatus according to a sixth embodiment of the present invention.

FIG. 14 is a diagram showing a configuration of a radiotherapy apparatus according to a seventh embodiment of the present invention.

FIG. 15 is a diagram showing the processing contents of a radiotherapy apparatus according to an eighth embodiment of the present invention.

FIG. 16 is a diagram showing a configuration of a conventional radiotherapy apparatus.

FIG. 17 is a diagram showing an operation of a conventional radiotherapy apparatus.

FIG. 18 is a diagram showing an operation of the conventional radiotherapy apparatus.

[Explanation of symbols]

15 CARM linac, 15A regular linac,
16 therapeutic beams, 17 tumor markers, 18 tumors, 1
9 patients, 20 treatment table, 21a X-ray tube A, 21b
Collimator A, 21c X-ray A, 21d Image intensifier A, 21e TV camera A, 21f X
X-ray high-voltage device A, 22a X-ray tube B, 22b Collimator B, 22c X-ray B, 22d Image intensifier B, 22e TV camera B, 22f X-ray high-voltage device B, 23 Irradiation control unit, 24 Camera control unit (CCU) A, 25 Camera control unit (CCU) B, 26 Image input section A, 27 Recognition processing section A, 28 Image input section B, 29 Recognition processing section B, 30
Central processing unit, 30a statistical processing function, 31 trigger control unit, 32 image display unit, 33 monitor, 34 drive axis drive control unit, 35 drive range determination unit, 36 tracking range determination unit.

Continued front page    F-term (reference) 4C082 AC02 AC04 AC05 AC06 AE02                       AG53 AJ07 AN02 AR01                 4C093 AA09 AA25 EA06 EB02 FF17                       FF19 FF21 FF22                 5B057 AA08 BA03 CA08 CA12 CB08                       CB13 CD14 CH01 DA07 DA16                       DB02 DB09 DC16 DC22 DC34                 5L096 AA06 BA06 BA13 CA12 DA02                       FA14 FA34 FA67 FA69 HA07                       JA09 LA11

Claims (8)

[Claims] 1. A CARM linac for irradiating a tumor with a therapeutic beam, at least three tumor markers embedded in the vicinity of the tumor, and a first fluoroscope for imaging the tumor marker from a first direction. A second fluoroscopy device that simultaneously images the tumor marker from a second direction with the first fluoroscopy device; and first and second outputs from the first and second fluoroscopy devices. The first and second image input sections for digitizing the two fluoroscopic images, respectively, and the template image of the tumor marker registered in advance in the image information digitized by the first and second image input sections were applied. The first and second two-dimensional coordinates of the three tumor markers are obtained by executing template matching by the grayscale normalized cross-correlation method at a real-time level of a predetermined frame rate. A second recognition processing unit, three-dimensional coordinates of the three tumor markers based on the first and second two-dimensional coordinates calculated by the first and second recognition processing units, and these tumor markers A central processing unit for calculating an isocenter position, a treatment beam direction, and an irradiation field shape obtained from the three-dimensional coordinates, and an isocenter position, a treatment beam direction, and an irradiation field shape obtained from the three-dimensional coordinates of the obtained tumor marker And an irradiation control unit that controls irradiation of the treatment beam of the CARM linac according to the above. 2. Each drive of the CARM linac based on the correction amount of each drive axis of the CARM linac obtained from the isocenter position calculated by the three-dimensional coordinates of the tumor marker, the treatment beam direction, and the irradiation field shape. Each drive axis drive control section for driving and controlling the axis is further provided, and while performing the real-time position correction on the tumor moving around in the trunk by each drive axis drive control section, the irradiation control section performs tracking irradiation with the treatment beam. Claim 1 characterized by the above.
The described radiotherapy device. 3. The correction amount of each drive axis of the CARM linac obtained from the isocenter position calculated by the three-dimensional coordinates of the tumor marker, the treatment beam direction, and the irradiation field shape is controlled for each drive axis. In the case of exceeding a predetermined drivable range, each drive shaft drive control unit,
The radiotherapy apparatus according to claim 2, further comprising a drive range determination unit that stops the operation of the irradiation control unit. 4. When the isocenter position, the treatment beam direction, and the irradiation field shape calculated by the three-dimensional coordinates of the tumor marker exceed a predetermined trackable range, each drive axis drive controller, and The radiotherapy apparatus according to claim 2, further comprising a tracking range determination unit that stops the operation of the irradiation control unit. 5. A CARM linac for irradiating a tumor with a therapeutic beam, at least three tumor markers embedded in the vicinity of the tumor, and a first fluoroscope for imaging the tumor marker from a first direction. A second fluoroscopy device that simultaneously images the tumor marker from a second direction with the first fluoroscopy device; and first and second outputs from the first and second fluoroscopy devices. The first and second image input sections for digitizing the two fluoroscopic images respectively, and the template image of the tumor marker pre-registered on the image information digitized by the first and second image input sections were applied. The first and second two-dimensional coordinates of the three tumor markers are obtained by executing template matching by the grayscale normalized cross-correlation method at a real-time level of a predetermined frame rate. A second recognition processing unit, three-dimensional coordinates of the three tumor markers based on the first and second two-dimensional coordinates calculated by the first and second recognition processing units, and these tumor markers A central processing unit for calculating the isocenter position, the treatment beam direction, and the irradiation field shape obtained from the three-dimensional coordinates of the tumor marker.
It is possible to position each drive axis of the CARM linac before the treatment based on the isocenter position calculated by these coordinates, the treatment beam direction, and the correction amount of each drive axis obtained from the irradiation field shape. A characteristic radiotherapy device. 6. The tumor marker is used in four or more, and the central processing unit statistically processes four or more tumor marker coordinates to calculate the calculated isocenter position, treatment beam direction, and irradiation field shape. The radiotherapy apparatus according to claim 1, further comprising a statistical processing function for increasing the certainty of the radiotherapy. 7. The radiotherapy apparatus according to claim 1, further comprising a normal linac instead of the CARM linac. 8. The central processing unit sets an allowable value for the gantry angle of 0 deg or 180 deg when the corrected gantry angle is near 0 deg or 180 deg, and when the deviation amount is less than or equal to the allowable value. The radiotherapy apparatus according to claim 7, wherein the gantry angle is calculated by regarding 0 deg or 180 deg.