JP2004024387A - Method and apparatus for evaluating dislocation of radiation - Google Patents

Method and apparatus for evaluating dislocation of radiation Download PDF

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Publication number
JP2004024387A
JP2004024387A JP2002182619A JP2002182619A JP2004024387A JP 2004024387 A JP2004024387 A JP 2004024387A JP 2002182619 A JP2002182619 A JP 2002182619A JP 2002182619 A JP2002182619 A JP 2002182619A JP 2004024387 A JP2004024387 A JP 2004024387A
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Japan
Prior art keywords
position
radiation
frame
isocenter
radiation source
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JP2002182619A
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Japanese (ja)
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JP3905798B2 (en
Inventor
Shin Asano
Susumu Miki
三木 晋
浅野 伸
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Mitsubishi Heavy Ind Ltd
三菱重工業株式会社
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for evaluating dislocation of radiation from the isocenter in stereotaxic radiation therapy. <P>SOLUTION: A radiation source movably supported along an arc shape locus formed on a frame 40 is moved along the locus and a dummy head I to irradiate laser light in a direction same as the radiation alternative to the radiation source moving on a spherical surface drawn by rotating the frame 40 around a slanted shaft by a slanting mechanism so that the locus draws the spherical surface is mounted on the locus. On the other hand, a position of the isocenter is regulated by correcting with a correcting tool II and a light intercepting face of a CCD (charge coupled device) camera is horizontally positioned on the isocenter position to evaluate an irradiated position of the radiation by detecting dislocation on the light intercepting face of the center position of the laser light irradiated from arbitrary positions on the identical spherical surface based on the center position of the laser light formed on the light intercepting face on a prescribed reference position. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method and an apparatus for evaluating a positional deviation amount of a radiation irradiation position, and particularly to a method and apparatus for evaluating a positional deviation amount of a radiation irradiation position from an isocenter in a stereotactic radiotherapy apparatus that irradiates an affected part with radiation. It is useful.
[0002]
[Background Art]
As a method of performing treatment by irradiating radiation to an affected part such as a cancer lesion, there is stereotactic radiotherapy in which radiation is intensively applied to the affected part. In this stereotactic radiotherapy, the irradiation direction of radiation is changed on a spherical surface to irradiate the affected area with radiation from multiple directions, thereby minimizing irradiation to normal tissue and intensively and locally irradiating the affected area with radiation. Can be irradiated. That is, the radiation irradiated from each direction is always irradiated to the isocenter which is the center of the spherical surface, and the radiation amount at this isocenter becomes the integral value of the radiation amount irradiated from each direction, and becomes the maximum radiation amount. For this reason, if the isocenter and the diseased part are made to coincide with each other, it is possible to irradiate the diseased part intensively with the required dose of radiation while minimizing the irradiation of normal tissue with radiation.
[0003]
As a radiotherapy apparatus for performing such stereotactic radiotherapy, Cyberknife (trademark; Accurate Incorporated (USA)) that moves a radiation source to irradiate the affected area intensively, a C-arm type electron beam linac, and the like are available. is there.
[0004]
CyberKnife is equipped with a small electron beam linac as a radiation source at the tip of an industrial robot arm in which about 7 axes of multi-axis joints are connected in series, and controls the robot arm to move the radiation source to a specified position. This is a radiotherapy apparatus that irradiates the affected part with radiation from this prescribed position.
[0005]
The C-arm type electron beam linac mounts a radiation source on a large arc-shaped frame and tilts the frame together with the radiation source, thereby irradiating the affected part located at the isocenter, which is the center of the arc, with concentrated radiation.
[0006]
However, the cyber knife and the C-arm type electron beam linac have the following problems.
[0007]
In the cyber knife, since the robot arm has a cantilever structure, the robot arm is easily deformed by the load of the electron beam linac. In addition, since the movement of the robot arm is controlled by multiple joints, there is an accumulation of position errors at each joint. Therefore, there is a possibility that a deviation between the radiation source and the prescribed position occurs, and there is a problem in accuracy when precise irradiation is required. Also, in CyberKnife, since the robot arm has a multi-axis joint and cannot restrict the degree of freedom of the robot arm in a specific direction approaching the patient, the robot arm and the patient due to runaway of the control system that controls the robot arm, etc. It is extremely difficult to arrange a safety device for preventing a collision with the vehicle, and there is a safety problem.
[0008]
In the C-arm type electron beam linac, since a large frame is moved together with the radiation, a displacement between the isocenter and the irradiation point is likely to occur due to the deformation of the frame due to the load of the radiation source. There is no specific means for correction.
[0009]
[Problems to be solved by the invention]
The present inventors have newly developed a stereotactic radiotherapy apparatus that can solve the problems of the cyber knife and the C-arm type electron beam linac according to the related art as described above, and can position the irradiation position with high accuracy. This is a frame having an arc-shaped trajectory, a radiation source movably supported along the trajectory, a moving mechanism for moving the radiation source along the trajectory, and so that the trajectory draws a spherical surface. A tilting mechanism for rotating the frame about a tilting axis, a first swing mechanism for rotating the radiation source about one axis, and a second mechanism for rotating the radiation source about another axis different from the one axis. And a second swing mechanism.
[0010]
However, in order to irradiate the radiation to the isocenter with high accuracy from multiple directions by changing the position of the radiation source, even when the radiation source moves It is necessary to know how far the irradiated radiation is off the isocenter. However, no method has been established for evaluating such a displacement amount.
[0011]
In view of the above, the present invention provides a method and an apparatus for evaluating a positional deviation amount of a radiation irradiation position which is excellent in versatility for evaluating a positional deviation amount of a radiation irradiation position from an isocenter in stereotactic radiotherapy. Aim.
[0012]
[Means for Solving the Problems]
The configuration of the present invention that achieves the above object has the following features.
[0013]
1) A laser that irradiates a laser beam in the same direction as the radiation irradiated by the radiation source of a radiation therapy apparatus that irradiates radiation from a radiation source moving on the same spherical surface toward an isocenter that is the center of the spherical surface from multiple directions. While mounting the head,
The position of the isocenter is defined by a calibration jig, and the imaging surface of the imaging means is occupied horizontally at this isocenter position.
Based on the center position of the laser light formed on the imaging surface at the reference position, by detecting the amount of displacement of the center position of the laser light emitted from any position on the same spherical surface on the imaging surface, Evaluating the irradiation position of the radiation irradiated from the radiation source via the positional deviation amount of the irradiation position of the laser light.
[0014]
2) a frame having an arc-shaped trajectory, a radiation source movably supported along the trajectory, a moving mechanism for moving the radiation source along the trajectory, and a moving mechanism for moving the radiation source along the trajectory. A radiation irradiation position in a radiation therapy apparatus that irradiates radiation from a radiation source moving on the same spherical surface from multiple directions toward an isocenter that is the center of the spherical surface with a tilting mechanism that rotates the frame around a tilting axis A method for evaluating a displacement amount,
While mounting a laser head that irradiates laser light in the same direction as the radiation,
The position of the isocenter is defined by a calibration jig, and the imaging surface of the imaging means is occupied horizontally at this isocenter position.
Based on the center position of the laser light formed on the imaging surface at the reference position, by detecting the amount of displacement of the center position of the laser light emitted from any position on the same spherical surface on the imaging surface, Evaluating the irradiation position of the radiation irradiated from the radiation source via the positional deviation amount of the irradiation position of the laser light.
[0015]
3) a frame having an arc-shaped trajectory, a radiation source movably supported along the trajectory, a moving mechanism for moving the radiation source along the trajectory, and A tilting mechanism for rotating the frame around a tilting axis, a first oscillating mechanism for rotating the radiation source around a single axis at a specific position on the frame, and similarly at a specific position on the frame. A second oscillating mechanism for rotating the radiation source about the other axis different from the one axis, and radiating the radiation from the radiation source moving on the same spherical surface toward the isocenter which is the center of the spherical surface. A method for evaluating a positional deviation amount of a radiation irradiation position in a radiation therapy apparatus that irradiates from a direction,
While mounting a laser head that irradiates laser light in the same direction as the radiation,
By fixing a calibration rod having a transmission hole in the center part which penetrates in the vertical direction to the frame via a column so that the central axis coincides with the tilt axis, the lower end surface of the transmission hole faces the isocenter.
Then, with the laser head positioned at the apex position of the frame while the frame is positioned in a vertical plane, the reflecting means is placed on the upper surface at the position of the transmission hole of the calibration rod,
In this state, the laser head irradiates the laser light toward the reflection means, and at this time, the irradiation direction of the laser light is adjusted so that the optical path of the incident light and the reflected light with respect to the reflection means of the laser light coincides with each other. Storing the spatial position of the imaging unit at this time by contacting the imaging unit with the surface of the calibration rod facing the transmission hole from below,
Thereafter, the calibration rod is removed from the frame, and the imaging surface is horizontally occupied at the isocenter based on the stored information of the position of the imaging means,
With reference to the center position of the laser light formed on the imaging surface at such a reference position, by detecting the amount of displacement of the center position of the laser light irradiated from any position on the same spherical surface on the imaging surface. Evaluating an irradiation position of the radiation irradiated from the radiation source via a positional shift amount of the irradiation position of the laser light.
[0016]
4) a laser head mounted on a radiotherapy device for irradiating radiation from a radiation source moving on the same spherical surface toward an isocenter which is the center of the spherical surface from multiple directions, and irradiating a laser beam in the same direction as the radiation;
A calibration jig for mechanically defining the position of the isocenter,
Imaging means for horizontally occupying the light receiving surface in the isocenter using this calibration jig,
Based on a center position of the laser light formed on the imaging surface at a predetermined reference position, a positional shift amount of the center position of the laser light irradiated from any position on the same spherical surface on the imaging surface is detected. It was configured to.
[0017]
5) a frame having an arc-shaped trajectory, a radiation source movably supported along the trajectory, a moving mechanism for moving the radiation source along the trajectory, and the moving mechanism so that the trajectory describes a spherical surface. A radiation irradiation position in a radiation therapy apparatus that irradiates radiation from a radiation source moving on the same spherical surface from multiple directions toward an isocenter that is the center of the spherical surface with a tilting mechanism that rotates the frame around a tilting axis A displacement amount evaluation device,
A laser head mounted on the frame and irradiating laser light in the same direction as the radiation,
A calibration jig for mechanically defining the position of the isocenter,
Imaging means for horizontally occupying the light receiving surface in the isocenter using this calibration jig,
Based on a center position of the laser light formed on the imaging surface at a predetermined reference position, a positional shift amount of the center position of the laser light irradiated from any position on the same spherical surface on the imaging surface is detected. It was configured to.
[0018]
6) a frame having an arc-shaped trajectory, a radiation source movably supported along the trajectory, a moving mechanism for moving the radiation source along the trajectory, and the moving mechanism so that the trajectory describes a spherical surface. A tilting mechanism for rotating the frame around a tilting axis, a first oscillating mechanism for rotating the radiation source around a single axis at a specific position on the frame, and similarly at a specific position on the frame. A second oscillating mechanism for rotating the radiation source about the other axis different from the one axis, and radiating the radiation from the radiation source moving on the same spherical surface toward the isocenter which is the center of the spherical surface. A displacement evaluation apparatus for a radiation irradiation position in a radiation therapy apparatus that irradiates from a direction, a laser head mounted on the frame and irradiating laser light in the same direction as the radiation,
A lower end surface of a transmission hole which is formed detachably with respect to the frame and has a center axis of the calibration rod coinciding with the tilt axis when mounted on the frame, and is a through-hole formed in a central portion of the calibration rod. A calibration jig having a calibration rod formed so as to face the isocenter,
Reflecting means mounted on the upper surface of the calibration rod at the position of the transmission hole to form a horizontal plane,
The space is fixed to the XYZ stage so that the space can be freely moved and the space position of the space can be known. And imaging means configured so that the imaging surface can be horizontally occupied in a plane including the isocenter,
Based on a center position of the laser light formed on the imaging surface at a predetermined reference position, a positional shift amount of the center position of the laser light irradiated from any position on the same spherical surface on the imaging surface is detected. It was configured to.
[0019]
7) The apparatus for evaluating a displacement of a radiation irradiation position according to any one of 4) to 6) above,
The laser head shall be mounted in place of the radiation source and supported to be movable along the trajectory of the frame.
[0020]
8) The apparatus for evaluating a displacement of a radiation irradiation position according to any one of 4) to 6) above,
The laser head and the radiation source are formed as an integral structure, and the relative position of the reflecting means with respect to the radiation source with respect to the optical axis position of the radiation source is formed so as to be adjustable. The laser beam can be reflected by the reflecting means so that an optical axis coincides with an optical axis of radiation irradiated by the radiation source.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0022]
Prior to describing a method and an apparatus for evaluating a positional deviation amount of a radiation irradiation position according to the present embodiment, an overview of a stereotactic radiotherapy apparatus to which the method is applied will be described with reference to FIGS.
[0023]
As shown in FIG. 1, the radiation treatment apparatus includes a treatment apparatus main body 1 and a treatment apparatus control unit that controls the treatment apparatus main body. The treatment apparatus main body 1 includes a bed 30 on which the patient 20 is placed and moved, an arc-shaped frame 40 installed so as to straddle the bed 30 in the width direction, a tilting mechanism 50 for rotating the frame 40, and a frame 40. The apparatus includes a radiation head (radiation source) 60 composed of a small electron beam linac and a moving mechanism 70 for moving the radiation head 60 in the circumferential direction of the frame 40.
[0024]
The bed 30 is moved in a longitudinal direction (X-axis direction), a width direction of the bed 30 (Y-axis direction), and a vertical direction (Z direction) by a built-in bed driving mechanism. The bed 30 is provided with a bed position detector (not shown) for detecting the position of the bed 30.
[0025]
The frame 40 has an arc shape and is made of a material such as aluminum which is lightweight and has excellent rigidity. In the present apparatus, the center point A of the arc formed by the frame 40 is arranged at a distance of about 90 cm from the inner circumference of the frame 40, but it can be set arbitrarily according to the target treatment form. An arc-shaped guide rail (track and dispersion supporting portion) 42 is provided on a side surface 41 a of the frame 40 facing the vertical direction (Z-axis direction). The guide rail 42 is made of a material having excellent rigidity (for example, a SUS material or the like) similarly to the frame 40. The center point of the arc formed by the guide rail 42 is provided so as to coincide with the center point A of the arc formed by the frame 40. In the present invention, the distance from the guide rail 42 to the center point A of the arc is about 1 m. However, this can also be set arbitrarily according to the target treatment form.
[0026]
The guide rail 42 is also provided on the other side surface 41b of the frame 40, as shown in FIG. A magnetic scale 43 is provided on the inner peripheral surface 41c of the frame 40 along the circumferential direction. Further, the frame 40 is provided with arms 44 so as to face each other with the center point A interposed therebetween.
[0027]
The arm 44 extends in the Y-axis direction and then bends in the X-axis direction, as shown in FIG. At portions of the arm 44 extending in the X-axis direction, tilting axes 45a and 45b parallel to the Y-axis are provided. These tilting shafts 45a and 45b are supported by mounts 46a and 46b installed on both sides of the bed 30, respectively. The gantry 46a, 46b is provided with a tilting mechanism 50 for rotating the tilting shafts 45a, 45b, respectively. The tilting mechanism 50 includes bearings 51a and 51b that rotatably support the tilting shafts 45a and 45b, a motor 52 that applies a rotating force to the tilting shaft 45a, and a speed reducer (not shown). To rotate the frame 40 around the tilt axes 45a and 45b. A rotary encoder (second angle detector) 53 that detects the rotation angle of the frame 40 is provided on the tilt shaft 45b.
[0028]
As shown in FIG. 2, the radiation head 60 is attached to the holding frame 62 via a swing shaft (uniaxial line) S provided on both side surfaces extending in the Y-axis direction. The emission section 66 (shown in FIG. 5) of the radiation head 60 attached to the holding frame 62 is disposed on an axis B connecting the tilting axes 45a and 45b of the frame 40. The holding frame 62 is provided with a first swing mechanism 63 that rotates the radiation head 60 around the swing axis S. The first oscillating mechanism 63 includes bearings 63a and 63b rotatably supporting the oscillating shaft S, a motor 63c for rotating the oscillating shaft S supported by the bearing 63b, and the oscillating shaft S rotating. An optical encoder (third angle detector) 63d for detecting a rotation angle. The holding frame 62 is attached to the moving mechanism 70 via the second swing mechanism 64.
[0029]
FIG. 3 is a cross-sectional view of the second swing mechanism 64 and the moving mechanism 70 along the line BB in FIG. As clearly shown in the figure, the second swing mechanism 64 rotates the holding frame 62 around a swing axis T (other axis) parallel to the X axis. The oscillating shaft T is provided so as to be orthogonal to the oscillating shaft S and to pass above the emission part 66 of the radiation head, and is rotated by a bearing (disposed in the speed reducer) 64 a of the second oscillating mechanism 64. Supported as possible. An optical encoder 64b (fourth angle detector) for detecting the rotation angle of the oscillating shaft T is provided inside the oscillating shaft T. A pulley 64c is provided at an end of the swing shaft T. A belt 64e extends between the pulley 64c and a pulley 64d rotatably attached to the moving mechanism 70 below the bearing 64a. The pulley 64d is connected to a motor 64f installed in the moving mechanism 70. The motor 64f rotates the swing shaft T by rotating the pulley 64d and sending out the belt 64e. As a result, the radiation head 60 is set around the swing axis T of the radiation head 60.
[0030]
The moving mechanism 70 includes a traveling platform 71 supported by the frame 40 and a belt 72 (shown in FIGS. 1 and 4). The belt 72 is stretched along the upper surface 41d of the frame 40, and both ends thereof are fixed to the frame 40 by a belt tensioner (holding portion) 72a. The traveling platform 71 has a U-shape in cross section, and is installed so as to surround both side surfaces 41a and 41b of the frame and the inner peripheral surface 41c. A second swing mechanism 64 is attached to a side portion 71a of the traveling platform 71 facing the side surface 41a of the frame. The side portion 71a is provided with a linear guide 73 that is engaged with the guide rail 42 provided on the side surface 41a of the frame 40.
[0031]
As shown in FIG. 2, two linear guides 73 are provided at intervals in the circumferential direction of the guide rail 42. A linear guide 74 that is engaged with the guide rail 42 provided on the side surface 41b of the frame 40 is also provided on a side portion 71b of the traveling platform 71 that faces the side surface 41b of the frame 40. The linear guide 74 is formed long in the circumferential direction of the guide rail 42. As described above, by engaging the linear guides 73 and 74 with the guide rails 42, the load between the traveling platform 71, the holding frame 62 attached to the traveling platform 71, and the radiation head 60 is reduced on both sides of the frame 40. The guide rails 42 provided on each of 41a and 41b are supported separately.
[0032]
A motor 75a is attached to the side 71b of the traveling platform 71. A pulley 75c is provided at a tip of a rotation shaft 75b of the motor 75a. A drive belt 75d is hung on the pulley 75c. The driving belt 75d is also hung on a driving pulley 76 provided above the side portion 71b. The rotating shaft 76a of the driving pulley 76 is supported by a bearing (disposed in the reduction gear) 76b. The end of the rotating shaft 76a is connected to a moving pulley 77 provided to face the driving pulley 76.
[0033]
Therefore, when the rotating shaft 75b is rotated by the motor 75a, the driving belt 75d is sent out, and the driving pulley 76 is rotated. When the driving pulley 76 rotates, a rotational force is transmitted from the rotation shaft 76a of the driving pulley 76 to the moving pulley 77, and the moving pulley 77 rotates. As shown in FIG. 4, four delivery pulleys 78 are provided on both sides of the moving pulley 77 along the circumferential direction of the frame 40. A belt 72 is alternately arranged vertically on the delivery pulley 78 and the movement pulley 77. The rotation of the delivery pulley 78 and the movement pulley 77 causes the belt 72 to move in the circumferential direction of the guide rail 42. Sent to Thereby, the traveling platform 71 connected to the belt 72 moves the guide rail 42 in the circumferential direction.
[0034]
As shown in FIG. 3, a sensor head 79 for reading the magnetic scale 43 is provided on the bottom 71 c of the traveling platform 71 facing the inner peripheral surface 41 c of the frame 40. The sensor head 79 detects the angle between the trajectory of the radiation source 60 moving along the guide rail 42 and the center point A.
[0035]
FIG. 5 is a sectional view of the radiation head 60. Reference numeral 65 in the figure denotes a rectangular parallelepiped cover. The electron beam linac 60a is housed in the cover 65. The emission section 66 of the electron beam linac 60 a is provided at the center of the lower surface of the cover 65. An X-ray having an energy of 4 MeV to 10 MeV is emitted from the emission unit 66 in a direction indicated by an arrow C in the drawing. Reference numeral 67a in the figure denotes an exhaust pump. This pump 67a exhausts the inside of the acceleration pipe 67c via the exhaust pipe 67b. The acceleration tube 67c accelerates an electron beam emitted from an electron gun (not shown) provided above the acceleration tube 67c. The electron beam accelerated by the acceleration tube 67c collides with a target 68a provided at the tip of the acceleration tube 67c, and generates an X-ray. The X-ray passes through the primary collimator 68b and is guided to the filter 68c, and the intensity is averaged in the process of passing through the filter 68c. The X-rays that have passed through the filter 68c are irradiated by the secondary collimator 68d and then emitted from the emission section 66 through the dose measuring means 69 after the irradiation directions are aligned. The dose measuring unit 69 measures the dose of the passed X-ray.
[0036]
As described above, in the radiation therapy apparatus 1, the load between the radiation head 60 and the traveling platform 71 is dispersed and supported by the guide rails 42 provided on both side surfaces 41a and 41b of the frame 40. The guide rail 42 and the frame 40 are not distorted by the load between the carriage 60 and the traveling platform 71. Therefore, the path on which the radiation head 60 moves is maintained in an arc shape. Further, since the radiation head 60 is guided along the guide rail 42 forming the trajectory, the radiation head 60 moves accurately along the trajectory. In addition, since the moving mechanism 70 is composed of a combination of the belt 72, the moving pulley 76, and the motor 75a, which hardly causes an error due to the assembling accuracy, the radiation head 60 is reliably moved to a predetermined position.
[0037]
Next, the operation of the treatment apparatus main body 2 will be described.
[0038]
When the moving mechanism 70 is driven, the radiation head 60 moves in the circumferential direction of the guide rail 42 together with the traveling table 71. Thereby, the radiation head 60 moves along an arc-shaped trajectory centered on the center point A. When the tilting mechanism 50 is driven, the frame 40 tilts in the X-axis direction about the tilting shafts 45a and 45b as shown in FIG. As a result, the frame 40 moves on a spherical surface centered on the center point A. Therefore, by rotating the frame 40 around the tilting axes 45a and 45b and moving the radiation head 60 in the circumferential direction of the guide rail 42, the radiation head 60 can be moved to an arbitrary point on the spherical surface around the center point A. Will be placed in Thus, the center point A can be irradiated with X-rays from multiple directions. That is, the center point A in this case is the isocenter.
[0039]
Further, when the first swing mechanism 63 is driven to rotate the radiation head 60 around the swing axis S parallel to the Y axis, the irradiation direction of the X-ray emitted from the emission unit 66 changes, and the irradiation point is changed. It moves from the center point A in the X-axis direction. Further, when the second swing mechanism 64 is driven to rotate the holding frame 62 together with the radiation head 60 around the swing axis T parallel to the X axis, the irradiation direction of the X-ray emitted from the emission unit 66 changes. The irradiation point moves from the center point A in the Y-axis direction. Therefore, by rotating the radiation head 60 with the first swing mechanism 63 and the second swing mechanism 64, it is possible to irradiate the X-ray from multiple directions even at a point away from the center point A. This enables three-dimensional irradiation in accordance with the shape of the affected part. Furthermore, by using the first swing mechanism 63 and the second swing mechanism 64, the irradiation direction of the X-ray is changed without moving the traveling platform 62 and the frame 40, and the patient's breathing, heartbeat, internal organ movement, etc. X-rays are also accurately applied to the moving affected part.
[0040]
The position where the radiation head 60 is arranged is, for example, as shown in FIG. 7, the position of the radiation head 60 and the frame 40 when the frame 40 is oriented vertically and the radiation head 60 is arranged right above the center point A. As a base point, the rotation angle た obtained by rotating the frame 40 about the axis B from the base point and the movement angle θ formed by the trajectory of the radiation head 60 around the center point A can be expressed.
[0041]
When the radiation head 60 is rotated about the oscillating axis S by the rotation angle α, the distance that the irradiation point moves in the X-axis direction, and when the radiation head 60 is rotated about the oscillating axis T by the rotation angle β The distance by which the irradiation point moves in the Y-axis direction can be represented by the distance I from the center point A to the intersection with the swing axes S and T. Therefore, if the position of the irradiation point at the position of the radiation head represented by the rotation angle Ψ and the movement angle θ is obtained in advance, by adjusting the rotation angle α and the rotation angle β, the desired position of the irradiation point can be obtained. Can be adjusted to
[0042]
As described above, by driving the moving mechanism 70 and the tilting mechanism 50, the radiation head 60 can be occupied at an arbitrary point on the spherical surface centered on the center point A, whereby the center point A becomes an isocenter, and from multiple directions. The irradiated radiation can be concentrated on this isocenter. Here, the position where the radiation head 60 is disposed is, for example, as shown in FIG. 7, when the frame 40 is oriented vertically and the radiation head 60 and the frame 40 when the radiation head 60 is disposed immediately above the center point A. The rotation head し て is represented by a rotation angle た obtained by rotating the frame 40 around the axis B from the base point, and a movement angle θ formed by the trajectory of the movement of the radiation head 60 around the center point A. Is controlled on a predetermined spherical surface.
[0043]
For this reason, theoretically, the radiation emitted from the radiation head 60 at each position on the predetermined spherical surface should go to the center point (isocenter) A. Error may occur. Therefore, it is necessary to evaluate this error as a positional shift amount of the radiation irradiation position with respect to the isocenter. This is for correcting the position shift amount and controlling the radiation head 60 to a predetermined position with high accuracy.
[0044]
The apparatus for evaluating the positional deviation of the radiation irradiation position according to the present embodiment evaluates the positional deviation of the radiation head 60 in the radiotherapy apparatus shown in FIG. 1. The components are the same as those of the treatment device. However, it has a laser head, a calibration jig, a CCD camera, and the like as constituent elements unique to this embodiment.
[0045]
FIGS. 8A and 8B are explanatory views conceptually showing the displacement amount evaluating apparatus according to the present embodiment, wherein FIG. 8A is a view of the apparatus from the front, and FIG. 8B is a view of the apparatus of FIG. First, an outline of the position shift amount evaluation apparatus will be described with reference to FIGS. Note that, in both figures, the same parts as those in FIGS.
[0046]
As shown in FIG. 8, the position shift amount evaluation apparatus has a laser head I mounted in place of the radiation head 60 of the radiation treatment apparatus shown in FIG. 1, and a CCD camera III is moved to a predetermined position using a calibration jig II. Is positioned. That is, the laser head I is supported by the holding frame 62 via the first swing mechanism 63 shown in FIG. The holding frame 62 is supported by the traveling platform 71 via the second swing mechanism 64. As a result, similarly to the radiation head 60, the laser head I can tilt (tilt and pan) in the XZ plane and the YZ plane.
[0047]
Accordingly, the laser head I freely moves on the circular arc of the frame 40, and rotates together with the frame 40 as the tilting mechanism 50 (see FIG. 1) rotates to drive each position. Thus, a predetermined tilt and pan operation can be performed. That is, it is configured to be able to move on a predetermined spherical surface defined by the shape of the frame 40 in exactly the same manner as the radiation head 60 and reproduce the same posture. At the same time, the laser head I is configured to be able to emit laser light in the same irradiation direction as the radiation instead of the radiation emitted from the radiation head 60. As a result, the laser head I can reproduce exactly the same operation as the operation of the radiation head 60 of the radiation therapy apparatus shown in FIG. Note that “mounting the laser head I instead of the radiation head 60” means that the laser head I is held by the holding frame 62 (FIG. 2) so that the center point of the laser head I coincides with the center point A shown in FIG. 1 etc.). Thereby, the optical axis of the laser beam emitted from the laser head I and the optical axis of the radiation emitted from the radiation head 60 can be matched, and the operation of the radiation head 60 can be completely simulated.
[0048]
The calibration jig II is configured so that both ends thereof can be attached to and detached from the arm 44 so that the center axis thereof coincides with the axis B (see FIG. 2). Therefore, the center point A exists on the center axis of the calibration jig II. The CCD camera III is mounted on an XYZ stage V provided on a surface plate IV. The XYZ stage V is formed so as to be movable in each of the XYZ axis directions. Therefore, the CCD camera III can move to an arbitrary position in space by driving the XYZ stage V 1.
[0049]
As shown in FIG. 9, a video signal which is an output signal of the CCD camera III is sent to the image processing device VI, and after being subjected to a predetermined process, is supplied to the intensity center-of-gravity detector VII. The intensity center-of-gravity detector VII detects the intensity distribution of the laser light L incident on the CCD camera III on the XY plane based on the video signal of the CCD camera III, and detects the coordinates of the intensity center O. Thus, in a state where the attitude of the laser head I is fixed (the state in which the first swing mechanism 63 and the second swing mechanism 64 shown in FIG. 2 are fixed; the same applies hereinafter), the laser head I is positioned at each position on the spherical surface. By irradiating the laser beam L from and detecting the coordinates of the intensity center, the amount of deviation of each intensity center from the reference position can be detected. Such a shift amount can be obtained by the calculation of the calculation processing unit VIII which calculates the shift amount based on the output signal of the intensity gravity center detecting unit VII.
[0050]
FIG. 10 is a front view showing the laser head I in detail. As shown in the figure, the laser head I irradiates a laser beam L simulating the radiation so as to coincide with the irradiation direction of the radiation actually emitted from the radiation head (see FIG. 1 and the like). A laser oscillator 80, which is a He-Ne laser, is mounted and supported on a holding frame 62 (see FIG. 1 and the like). Therefore, the first and second swing mechanisms 63 and 64 (see FIG. 1 and the like) can rotate around the pan axis and the tilt axis in FIG.
[0051]
The light emitted from the laser oscillator 80 is turned back by two mirrors 81a and 82a held by optical axis adjusting gimbals 81 and 82, and is emitted toward the isocenter. In the middle of the optical path at this time, pinholes 83 and 84 are provided at two places. The laser light L, which is the light emitted from the laser oscillator 80, is designed to pass through the pinholes 83 and 84 so that the optical axis reference for the laser head I is satisfied. That is, the optical axis of the laser beam L emitted from the laser oscillator 80 passing through the pinholes 83 and 84 and the central axis of the laser head I passing through the center point A (see FIG. 2) coincide with each other. is there.
[0052]
The ND filter 85 is for adjusting the intensity of the laser light L emitted from the laser head I and incident on the CCD camera III. The concave lens 86 and the convex lens 87 are for condensing the laser beam L so that the beam diameter of the laser beam L on the light receiving surface of the CCD camera III becomes a predetermined small diameter (for example, φ0.5 mm).
[0053]
FIGS. 11A and 11B are diagrams showing the calibration jig of the displacement amount evaluation apparatus according to the embodiment of the present invention in an extracted and enlarged manner, wherein FIG. 11A is a plan view, FIG. 11B is a front view, and FIG. (B) is an enlarged view showing a portion C of (b). As shown in these figures, the calibration jig II includes two columns 90 and 91 and a calibration rod 92. Here, as shown in FIG. 1, the left and right arms 44 are respectively formed with spigot holes 44a, and the base ends of the columns 90 and 91 are fixed to the spigot holes 44a, respectively. The calibration rod 92 is fixed to the arm 44 while maintaining a high-precision positional relationship with the arm 44 by supporting both ends of the column 90 and 91 at the distal ends thereof.
[0054]
More specifically, when the calibration jig II is mounted, first, the column 91 is inserted into the spigot hole 44a of the arm 44 on the right side in the figure, and is fixed with the bolt 93. Next, the calibration rod 92 is inserted into the hole 91a at the tip of the column 91 while being supported by a crane or the like. At this time, the calibration rod 92 is sufficiently moved to the column 91 side.
[0055]
Next, the column 90 is fixed to the spigot hole 44a of the arm 44 on the left side in FIG. Thereafter, the column 91 and the calibration rod 92 supported by a crane or the like are moved toward the column 90 and inserted into the hole 90 a of the column 90. Subsequently, the pins 94 are inserted into the pin holes formed in the calibration rod 92 and the column 90, and the calibration rod 92 is positioned. Finally, the calibration rod 92 is fixed with the bolt 95 also on the column 91 side.
[0056]
Here, the two spigot holes 44 are machined with a size of 0.05 mm and a geometrical tolerance with respect to the isocenter. The axis of the calibration rod 92 supported by the columns 90 and 91 coincides with the axis B of the tilt axis. Further, a laser transmission hole 92a and a concave portion 92b are formed in the center of the calibration rod 92. Here, the position of the laser transmission hole 92a is mechanically regulated by the pin 94 on the column 90 side, and coincides with the traveling axis center line (a perpendicular line passing through the center point A (see FIG. 2)). The concave portion 92b is formed on the lower surface side of the calibration rod 92, and the bottom surface thereof is configured to include the axis B. Therefore, the position of the isocenter is mechanically obtained by using the calibration jig II. That is, it is the intersection of the axis B and the optical axis of the laser beam L (see FIG. 10).
[0057]
The CCD camera III is occupied at the position of the isocenter. Here, the CCD camera III is mounted on an XYZ stage V. By manually moving a micrometer with respect to both X and Y axes of the XYZ stage V, the position in the XY plane (horizontal plane) is set at a distance of μm with respect to the laser transmission hole 92a. It is configured so that it can be finely adjusted on the order. Similarly, the position of the CCD camera III in the Z-axis direction can be finely adjusted in the order of μm by manually moving a micrometer in the Z-axis of the XYZ stage V 1.
[0058]
Evaluation of the amount of displacement using the above-described device for evaluating the amount of displacement is performed in the following manner.
[0059]
First, the calibration jig is set. Specifically, it is as described above with reference to FIG. Next, the swing mechanism is set. That is, the mechanical origin of the swing axis (pan and tilt) of the laser head I shown in FIG. 10 is set.
[0060]
Subsequently, as shown in FIG. 11D, the flat mirror 96 is set in the spigot hole formed on the upper surface of the laser transmission hole 92a of the calibration jig II for which the setting has been completed. The geometrical tolerance of the contact surface of the flat mirror 96 with the spigot hole is 0.01 mm, which corresponds to a tilt angle of 1/3000.
[0061]
Next, at the vertex position of the frame 40, the traveling platform 71 (see FIG. 1 and the like) is fixed to the frame (traveling shaft) 40 with pins or the like. This state is defined as the mechanical origin of the traveling axis. With respect to the tilt axis of the frame 40, a level gauge is installed on a flat portion formed on the arm 44, and is locked by a motor brake at a position where the level gauge becomes almost flat by the installed level gauge. That is, the surface including the frame 40 is made vertical. This state is defined as the mechanical origin of the tilt axis.
[0062]
From the above state, the offset amount up to the origin detection sensor (not shown) is acquired and stored in the control unit. The offset amount is an offset amount of each unit with respect to a predetermined origin position, and is a process necessary to ensure reproducibility of the position deviation amount evaluation. In other words, in the next positional deviation amount evaluation, the original position can be reproduced by the origin inspection sensor and the offset amount measured in advance, so that the predetermined positional deviation amount can be evaluated under the same conditions as the previous time. , Measurement reproducibility can be improved.
[0063]
As described above, the traveling axis and the tilting axis are initially set, that is, after securing the mechanical origin of both axes, the laser beam I is emitted from the laser head I toward the plane mirror 96 set on the calibration jig II. At this time, the first and second oscillating mechanisms 63 and 64 are driven so that the reflected light from the plane mirror 96 matches the incident light, and the oscillating axes (pan axis and tilt axis) S and T (FIG. 2) fine adjustment. As a result, the point where the optical axis reflected from the plane mirror 96 coincides with the incident optical axis is defined as the mechanical origin of the first and second drive axes 63 and 64 (see FIG. 2), and each axis is locked by the motor brake. . This state is defined as the mechanical origin of the swing axis (pan / tilt axis).
[0064]
Next, the CCD camera III is set. Specifically, the XYZ stage V is set on the surface plate IV, and the CCD camera III is set by a mounting jig. In this state, the Z-axis of the XYZ stage V is moved to the lowermost stroke end, and the surface plate IV or XYZ is arranged so that the light receiving surface 97 of the CCD camera III is located at a position facing the laser transmission hole 92 of the calibration jig II. The stage V is moved and fixed.
[0065]
In this state, the signal processing system shown in FIG. 9, which functions as a laser profiler, is driven to check the beam cross-sectional profile of the laser beam L, and to confirm that the beam has a predetermined beam diameter and intensity distribution (Gaussian distribution). At the same time, the CCD camera III is moved in the XY plane via the XYZ stage V so that the laser beam L is irradiated to an appropriate position on the light receiving surface 97 of the CCD camera III. Thereafter, the Z-axis of the XYZ stage V is raised until the tip of the CCD camera III comes into contact with the bottom surface of the concave portion 92b of the calibration jig II.
[0066]
With the tip of the CCD camera III in contact with the calibration jig II, the micrometer value of the Z-axis of the XYZ stage V is checked in advance. Next, the Z-axis of the XYZ stage V is lowered to release the contact state between the calibration jig II and the tip of the CCD camera III.
[0067]
Thereafter, the calibration jig II is removed from the arm 44 (see FIG. 1). The removal procedure is as follows. The pin 94 in which the column 90 and the calibration rod 92 are fitted is removed. Next, the bolt 95 fastening the column 91 and the calibration rod 92 is removed. Subsequently, a crane is set to a state where the calibration rod 92 can be supported.
[0068]
In this state, the calibration rod 92 is moved toward the column 91 and the column 90 is removed. Next, the calibration rod 92 is removed from the column 91 and moved out of the apparatus system by the crane. Next, the column 91 is removed.
[0069]
Thereafter, as described above, the Z-axis stage is moved based on the micrometer value of the Z-axis of the XYZ stage V which has been confirmed in a state where the tip of the CCD camera III is in contact with the calibration jig II. Is returned to the original position, and the Z-axis stage of the XYZ stage V further raises it by a predetermined amount Δl (the distance between the tip of the CCD camera III and the light receiving surface 97). Thus, the isocenter and the light receiving surface 97 of the CCD camera III can be matched with high accuracy.
[0070]
In such a state, the traveling platform 71 (see FIG. 1) can be freely moved by removing the pins or the like that fixed the traveling platform 71 to the frame 40 so that the traveling platform 71 can travel along the frame 40 (see FIG. 1). To be able to move to
[0071]
Thus, the preparation for the evaluation of the amount of displacement by the CCD camera III is completed. Thereafter, the traveling platform 71 (see FIG. 1) is moved along the frame 40 (see FIG. 1), and the frame 40 (see FIG. 1) is rotated around the tilting axis to move to an arbitrary position on the same spherical surface. The laser head I is occupied. The laser head I emits laser light L from each position toward the isocenter. The CCD camera III and its signal processing system detect the coordinates of the center position by receiving the laser beam L and performing predetermined signal processing. Thus, the amount of positional deviation of the laser light L emitted from the laser head I occupying an arbitrary position on the same spherical surface with respect to the isocenter can be quantitatively grasped.
[0072]
In the above embodiment, the laser head I is mounted instead of the radiation head 60, but the laser head I may be integrally attached to the radiation head 60. However, in this case, it is necessary to have a structure that can be adjusted so that the optical axis of the laser beam L emitted from the laser head I coincides with the optical axis of the radiation emitted from the radiation head 60. An apparatus having such an integrated structure of the laser head I and the radiation head 60 will be described as another embodiment of the present invention.
[0073]
FIGS. 12A and 12B are explanatory views conceptually showing a displacement amount evaluating apparatus according to the present embodiment, in which FIG. 12A is a view of the apparatus from the front, and FIG. 12B is a view of FIG. FIG. 13 is a view of the head portion shown in FIG. 12 viewed from below. FIG. 13A shows a state at the time of evaluation of the isocenter, and FIG. 13B shows a state at the time of treatment (normal time). In these figures, the same parts as those in FIG. 8 are denoted by the same reference numerals, and duplicate description will be omitted.
[0074]
As shown in FIG. 12, in this embodiment, the laser head I is disposed on the front surface of the radiation head 60, and the laser light L directed downward in the Z-axis in the drawing is emitted by the optical axis adjusting optical system. From the irradiation direction of the radiation irradiated from. That is, the optical axis of the laser light L is adjusted so that the optical axes of the two coincide.
[0075]
That is, when the isocenter is evaluated by irradiating the laser beam L, as shown in FIG. 13A, the optical path of the laser beam L emitted from the laser head I in the negative direction of the Z axis is The light is bent 90 ° in the negative direction and is incident on the mirror 102. The optical path of the laser light L incident on the mirror 102 is bent by 90 ° in the minus direction of the Z axis, so that the optical axis of the laser light L is adjusted in a direction coincident with the irradiation direction of the radiation irradiated from the radiation head 60. .
[0076]
Here, the mirror 102 is configured to move linearly along the guide 104 by the mirror driving means 103. As a result, the mirror 102 is configured to be able to approach and separate from the optical axis position of the radiation head 60.
[0077]
Therefore, in the evaluation of the isocenter, first, the relative position of the mirror 102 with respect to the radiation head 60 is adjusted so that the optical axis of the laser beam L emitted by the laser head I coincides with the optical axis of the radiation emitted by the radiation head 60. Adjust to After that, the evaluation of the isocenter is performed in the same manner as in the first embodiment.
[0078]
When the evaluation of the isocenter using the laser beam L has been completed and the treatment with radiation is to be performed, the mirror 102 is moved by the mirror driving means 103 to retract with respect to the optical axis of the radiation. Thus, the radiation head 60 can be irradiated with radiation. At this time, since the laser light L is unnecessary, the power of the laser head I is turned off or a light shielding plate is provided in front of the mirror 102, and the light shielding plate 102 shields the laser head I from light.
[0079]
8 to 11 are applied to the radiation therapy apparatus shown in FIG. 1 and the like, but are not limited thereto. Stereotactic radiotherapy that irradiates the affected area from multiple directions by changing the irradiation direction of the radiation emitted from the radiation source at an arbitrary position on the spherical surface, thereby irradiating the affected area with the isocenter coincidentally and locally. There is no particular limitation as long as it is a device. In short, a laser head that irradiates laser light instead of a radiation source is mounted on the main body of the apparatus so that it can move freely on the same spherical surface, while the isocenter is mechanically defined by a calibration jig. The imaging surface of the imaging means such as a CCD camera is occupied at the isocenter position, and the center of the laser light irradiated from any position on the same spherical surface with reference to the center position of the laser light formed on the imaging surface at the reference position. What is necessary is just to comprise so that the positional deviation amount of the position in the said imaging surface can be detected. Therefore, a radiation source is installed at the tip of an industrial robot arm with multi-axis joints connected in series, the robot arm is controlled to move the radiation source to a specified position, and the radiation is concentrated on the affected area from this specified position. The present invention can be applied to an irradiation device. In this case, an isocenter is defined by the calibration jig by providing a calibration jig that maintains a predetermined positional relationship with respect to the reference position of the industrial robot arm, and the imaging center is defined by the isocenter defined in this manner. What is necessary is just to make it the structure which matches a surface.
[0080]
【The invention's effect】
As described in detail with the above embodiments, the invention described in [Claim 1] is directed to irradiating radiation from a radiation source moving on the same spherical surface toward an isocenter which is the center of the spherical surface from multiple directions. A laser head for irradiating a laser beam in the same direction as the radiation emitted by the radiation source of the treatment apparatus is mounted, and the position of the isocenter is defined by a calibration jig. Occupied by the center position of the laser light formed on the imaging surface at the reference position, the amount of positional deviation of the center position of the laser light emitted from any position on the same spherical surface on the imaging surface. By evaluating the irradiation position of the radiation irradiated from the radiation source through the amount of displacement of the irradiation position of the laser light by detecting,
The irradiation condition of the radiation can be completely simulated by the laser light emitted from the laser head, and the arbitrary position on the same spherical surface can be determined based on the center position of the laser light formed on the imaging surface at the reference position via the laser light. Can be detected relative to the center position of the laser beam emitted from each position.
As a result, according to the present invention, it is possible to evaluate the irradiation position at each position of the radiation in the radiation treatment apparatus that irradiates radiation from multiple directions toward the isocenter, and to calibrate the radiation treatment apparatus based on the evaluation data. Can be performed with high accuracy.
[0081]
The invention described in [Claim 2] is a frame having an arc-shaped trajectory, a radiation source movably supported along the trajectory, and a moving mechanism for moving the radiation source along the trajectory, A tilt mechanism for rotating the frame around a tilt axis so that the orbit describes a spherical surface, and irradiating radiation from a radiation source moving on the same spherical surface toward an isocenter which is the center of the spherical surface from multiple directions. A method for evaluating a displacement amount of a radiation irradiation position in a radiation treatment apparatus, comprising: mounting a laser head for irradiating a laser beam in the same direction as the radiation, defining a position of the isocenter by a calibration jig, The position of the imaging surface of the imaging means is horizontally occupied at any position, and any position on the same spherical surface with reference to the center position of the laser light formed on the imaging surface at the reference position. Because through the positional displacement amount of the irradiation position of the laser light to evaluate the irradiation position of the radiation irradiated from the radiation source by detecting a positional deviation amount in the imaging plane of the center position of the laser beam al irradiated,
A frame having an arc-shaped trajectory, a radiation source movably supported along the trajectory, a moving mechanism for moving the radiation source along the trajectory, and the frame so that the trajectory describes a spherical surface. A radiotherapy apparatus having a tilting mechanism for rotating about a tilt axis and irradiating radiation from a radiation source moving on the same spherical surface to an isocenter which is the center of the spherical surface from multiple directions. The same operation and effect as the invention described in (1) are obtained.
[0082]
The invention described in [Claim 3] is a frame having an arc-shaped trajectory, a radiation source movably supported along the trajectory, and a moving mechanism for moving the radiation source along the trajectory, A tilting mechanism that rotates the frame around a tilting axis so that the trajectory describes a spherical surface, and a first swinging mechanism that rotates the radiation source around one axis at a specific position of the frame, A second oscillating mechanism for rotating the radiation source about the other axis different from the one axis at a specific position of the frame, so that the radiation from the radiation source moving on the same spherical surface A method for evaluating the amount of positional deviation of a radiation irradiation position in a radiation therapy apparatus that irradiates from multiple directions toward an isocenter that is the center of a laser beam, wherein a laser head that irradiates laser light in the same direction as the radiation is mounted. By fixing a calibration rod having a transmission hole in the center part which penetrates in the vertical direction to the frame via a column so that the central axis coincides with the tilt axis, the lower end surface of the transmission hole faces the isocenter. Thereafter, with the frame positioned in the vertical plane, the laser head is positioned at the apex of the frame, and a reflecting means is mounted on the upper surface of the calibration rod at the position of the transmission hole. Irradiating laser light from the laser head toward the means, and adjusting the irradiation direction of the laser light so that the optical path of the incident light and the reflected light with respect to the reflecting means of the laser light at this time coincides with each other; The calibration rod is brought into contact with the surface of the calibration rod facing the transmission hole from below, and the spatial position of the imaging unit at this time is stored. The image pickup surface is horizontally occupied at the isocenter based on the storage information of the position of the image pickup means, and the center position of the laser light formed on the image pickup surface at the reference position is used as a reference. Estimating the irradiation position of the radiation irradiated from the radiation source through the amount of displacement of the irradiation position of the laser light by detecting the amount of displacement of the center position of the laser light irradiated from any position on the imaging surface Therefore, the irradiation condition of the radiation can be completely simulated by the laser light irradiated from the laser head, and the center of the laser light formed on the imaging surface at the reference position through the laser light can be used as a reference for the same spherical surface. It is possible to detect a relative positional shift amount of the center position of the laser beam emitted from each of the above arbitrary positions.
At this time, the laser light at the reference position is adjusted so that the optical path of the incident light to the reflecting means and the reflected light coincide with each other, and this optical path can be made to coincide with the perpendicular, so that the optical path of the laser light and the tilt The point of intersection with the axis can be made to exactly coincide with the isocenter.
As a result, the amount of positional deviation can be grasped as the amount of deviation from the isocenter, and calibration of the radiotherapy apparatus with respect to the isocenter can be performed with high accuracy based on the evaluation data.
Incidentally, according to the present invention, the isocenter position of the radiotherapy apparatus can be evaluated with a resolution of 0.1 mm or less, and the irradiation accuracy of the radiotherapy apparatus can be reduced to 0 based on the calibration data obtained by the isocenter displacement evaluation apparatus. .1 mm.
[0083]
The invention described in [Claim 4] is mounted on a radiotherapy apparatus that irradiates radiation from a radiation source moving on the same spherical surface toward an isocenter that is the center of the spherical surface from multiple directions, and is mounted in the same direction as the radiation. A laser head for irradiating a laser beam, a calibration jig for mechanically defining the position of the isocenter, and an imaging unit for horizontally occupying the light receiving surface on the isocenter using the calibration jig; The apparatus is configured to detect a position shift amount of the center position of the laser light irradiated from any position on the same spherical surface on the imaging surface with reference to a center position of the laser light formed on the imaging surface at a reference position. Because
The irradiation condition of the radiation can be completely simulated by the laser light emitted from the laser head, and the arbitrary position on the same spherical surface can be determined based on the center position of the laser light formed on the imaging surface at the reference position via the laser light. Can be detected relative to the center position of the laser beam emitted from each position.
As a result, according to the present invention, it is possible to evaluate the irradiation position at each position of the radiation in the radiation treatment apparatus that irradiates radiation from multiple directions toward the isocenter, and to calibrate the radiation treatment apparatus based on the evaluation data. Can be performed with high accuracy.
[0084]
The invention described in [Claim 5] is a frame having an arc-shaped trajectory, a radiation source movably supported along the trajectory, and a movement mechanism for moving the radiation source along the trajectory, A tilt mechanism for rotating the frame around a tilt axis so that the orbit describes a spherical surface, and irradiating radiation from a radiation source moving on the same spherical surface toward an isocenter which is the center of the spherical surface from multiple directions. And a calibration head that is mounted on the frame and irradiates a laser beam in the same direction as the radiation, and mechanically defines the position of the isocenter. A jig and imaging means for horizontally occupying the light receiving surface at the isocenter using the calibration jig, and the laser light formed on the imaging surface at a predetermined reference position. With respect to the center position, since it is configured to detect the positional deviation amount in the imaging plane of the center of any of the laser light irradiated from each position on the same spherical surface,
A frame having an arc-shaped trajectory, a radiation source movably supported along the trajectory, a moving mechanism for moving the radiation source along the trajectory, and the frame so that the trajectory describes a spherical surface. A radiotherapy apparatus having a tilting mechanism for rotating about a tilt axis and irradiating radiation from a radiation source moving on the same spherical surface to an isocenter which is the center of the spherical surface from multiple directions. The same operation and effect as the invention described in (1) are obtained.
[0085]
The invention described in [Claim 6] is a frame having an arc-shaped trajectory, a radiation source movably supported along the trajectory, and a moving mechanism for moving the radiation source along the trajectory, A tilting mechanism that rotates the frame around a tilting axis so that the trajectory describes a spherical surface, and a first swinging mechanism that rotates the radiation source around one axis at a specific position of the frame, A second oscillating mechanism for rotating the radiation source about the other axis different from the one axis at a specific position of the frame, so that the radiation from the radiation source moving on the same spherical surface An apparatus for evaluating a positional deviation of a radiation irradiation position in a radiation therapy apparatus for irradiating from multiple directions toward an isocenter, which is a center of a laser, which is mounted on the frame and irradiates a laser beam in the same direction as the radiation. The head and a transmission hole, which is formed detachably with respect to the frame, has a center axis of the calibration rod coinciding with the tilt axis when mounted on the frame, and is a through-hole formed in the center of the calibration rod. A calibration jig having a calibration rod formed so that the lower end face faces the isocenter, a reflecting means mounted on the upper surface of the calibration rod at the position of the transmission hole to form a horizontal plane, and fixed to an XYZ stage. While being configured so that the space can be freely moved and configured to be able to know its own spatial position, the imaging surface is brought into contact with the lower surface of the calibration rod at the position of the transmission hole from below, so that the imaging surface is Imaging means configured to be horizontally occupied in a plane including the isocenter, and a center of the laser light formed on the imaging plane at a predetermined reference position. Based on the location, since it is configured to detect the positional deviation amount in the imaging plane of the center of any of the laser light irradiated from each position on the same spherical surface,
The irradiation condition of the radiation can be completely simulated by the laser light emitted from the laser head, and the arbitrary position on the same spherical surface can be determined based on the center position of the laser light formed on the imaging surface at the reference position via the laser light. Can be detected relative to the center position of the laser beam emitted from each position.
As a result, according to the present invention, it is possible to evaluate the irradiation position at each position of the radiation in the radiation treatment apparatus that irradiates radiation from multiple directions toward the isocenter, and to calibrate the radiation treatment apparatus based on the evaluation data. Can be performed with high accuracy.
[0086]
According to a seventh aspect of the present invention, in the apparatus for evaluating a positional deviation of a radiation irradiation position according to any one of the fourth to sixth aspects, the laser head is mounted instead of the radiation source. It is supported movably along the trajectory of the frame,
At the time of evaluation of the isocenter, a laser head is attached to the frame instead of the radiation source. At the time of treatment, the laser head is detached, and a radiation source is attached instead to perform a predetermined treatment operation. In this case, effects similar to those of the inventions described in [claims 4] to [6] are obtained.
[0087]
The invention described in [Claim 8] is a device for evaluating a displacement of a radiation irradiation position according to any one of [Claim 4] to [Claim 6], wherein the laser head and the radiation source are integrated. The radiation source irradiates the optical axis of the laser light emitted by the laser head by forming the reflecting means relative to the radiation source with respect to the optical axis position of the radiation source. Since it was formed so as to be able to reflect the laser beam with the reflection means so as to coincide with the optical axis of the radiation,
The following effects can be expected with respect to the invention described in [Claim 7]. That is, since there is no need to replace the laser head I and the radiation source when transitioning from the isocenter evaluation to the treatment, the time required for the treatment can be reduced, the efficiency can be improved, and the replacement of the two is required. It is possible to prevent the occurrence of an error due to a mounting error or the like.
[Brief description of the drawings]
FIG. 1 is a front view showing a radiotherapy apparatus to which an embodiment of the present invention is applied.
FIG. 2 is a top view of the radiotherapy apparatus shown in FIG.
FIG. 3 is a sectional view taken along line BB in FIG. 2;
FIG. 4 is a front view illustrating a radiation head and a moving mechanism of the radiation therapy apparatus illustrated in FIG. 1;
FIG. 5 is a sectional view of a radiation head of the radiation therapy apparatus shown in FIG.
FIG. 6 is a side view of the radiotherapy apparatus shown in FIG. 1;
FIG. 7 is an explanatory view conceptually showing a reference of a position of a radiation head of the radiation therapy apparatus shown in FIG.
FIGS. 8A and 8B are explanatory views conceptually showing a displacement amount evaluation apparatus according to the embodiment of the present invention, wherein FIG. 8A is a front view of the apparatus, and FIG. FIG.
FIG. 9 is a block diagram showing a signal processing system of the displacement evaluation apparatus according to the embodiment of the present invention;
FIG. 10 is a front view showing a laser head I extracted and enlarged in the displacement evaluation apparatus according to the embodiment of the present invention;
FIGS. 11A and 11B are diagrams illustrating a calibration jig of the displacement amount evaluation apparatus according to the embodiment of the present invention in an extracted and enlarged manner, wherein FIG. 11A is a plan view, FIG. 11B is a front view, and FIG. FIG. 2A is a right side view, and FIG. 2D is an enlarged view showing a portion C of FIG.
FIGS. 12A and 12B are explanatory views conceptually showing a misregistration amount evaluation apparatus according to another embodiment of the present invention, wherein FIG. 12A is a front view of the apparatus, and FIG. FIG.
13A and 13B are views of the head portion shown in FIG. 12 viewed from below, where FIG. 13A shows a state at the time of evaluation of the isocenter, and FIG. 13B shows a state at the time of treatment (normal time).
[Explanation of symbols]
I laser head
II Calibration jig
III CCD camera
V XYZ stage V
1 radiotherapy equipment
40 frames
42 Guide rails (tracks and distributed support)
45a, 45b tilt axis
50 Tilt mechanism
60 Radiation head (radiation source)
63 First swing mechanism
64 Second swing mechanism
70 Moving mechanism
80 Laser oscillator
90,91 column
92 Calibration rod
92a Laser transmission hole
96 flat mirror
97 light receiving surface
101, 102 mirror
103 mirror driving means
S Swing axis (uniaxial)
T Pivot axis (other axis)
L laser light

Claims (8)

  1. A laser head that irradiates a laser beam in the same direction as the radiation irradiated by the radiation source of a radiation treatment apparatus that irradiates radiation from a radiation source moving on the same spherical surface toward an isocenter that is the center of the spherical surface from multiple directions. On the other hand,
    The position of the isocenter is defined by a calibration jig, and the imaging surface of the imaging means is occupied horizontally at this isocenter position.
    Based on the center position of the laser light formed on the imaging surface at the reference position, by detecting the amount of displacement of the center position of the laser light emitted from any position on the same spherical surface on the imaging surface, A method for evaluating a displacement amount of a radiation irradiation position, comprising: evaluating a radiation irradiation position of radiation irradiated from the radiation source via a displacement amount of a laser light irradiation position.
  2. A frame having an arc-shaped trajectory, a radiation source movably supported along the trajectory, a moving mechanism for moving the radiation source along the trajectory, and the frame so that the trajectory describes a spherical surface. A displacement of a radiation irradiation position in a radiation therapy apparatus for irradiating radiation from a radiation source moving on the same spherical surface to an isocenter which is the center of the spherical surface from multiple directions and having a tilting mechanism for rotating about a tilting axis. A quantity evaluation method,
    While mounting a laser head that irradiates laser light in the same direction as the radiation,
    The position of the isocenter is defined by a calibration jig, and the imaging surface of the imaging means is occupied horizontally at this isocenter position.
    Based on the center position of the laser light formed on the imaging surface at the reference position, by detecting the amount of displacement of the center position of the laser light emitted from any position on the same spherical surface on the imaging surface, A method for evaluating a displacement amount of a radiation irradiation position, comprising: evaluating a radiation irradiation position of radiation irradiated from the radiation source via a displacement amount of a laser light irradiation position.
  3. A frame having an arc-shaped trajectory, a radiation source movably supported along the trajectory, a moving mechanism for moving the radiation source along the trajectory, and the frame so that the trajectory describes a spherical surface. A tilting mechanism for rotating about a tilt axis, a first oscillating mechanism for rotating the radiation source about one axis at a specific position on the frame, and the radiation source at a specific position on the frame. And a second swing mechanism for rotating the axis about the other axis different from the one axis, from a radiation source moving on the same spherical surface toward the isocenter which is the center of the spherical surface from multiple directions. A method for evaluating a displacement amount of a radiation irradiation position in a radiation therapy apparatus for irradiation,
    While mounting a laser head that irradiates laser light in the same direction as the radiation,
    By fixing a calibration rod having a transmission hole in the center part which penetrates in the vertical direction to the frame via a column so that the central axis coincides with the tilt axis, the lower end surface of the transmission hole faces the isocenter.
    Then, with the laser head positioned at the apex position of the frame while the frame is positioned in a vertical plane, the reflecting means is placed on the upper surface at the position of the transmission hole of the calibration rod,
    In this state, the laser head irradiates the laser light toward the reflection means, and at this time, the irradiation direction of the laser light is adjusted so that the optical path of the incident light and the reflected light with respect to the reflection means of the laser light coincides with each other. Storing the spatial position of the imaging unit at this time by contacting the imaging unit with the surface of the calibration rod facing the transmission hole from below,
    Thereafter, the calibration rod is removed from the frame, and the imaging surface is horizontally occupied at the isocenter based on the stored information of the position of the imaging means,
    With reference to the center position of the laser light formed on the imaging surface at such a reference position, by detecting the amount of displacement of the center position of the laser light irradiated from any position on the same spherical surface on the imaging surface. A method of evaluating a displacement amount of a radiation irradiation position, comprising: evaluating an irradiation position of radiation irradiated from the radiation source via a displacement amount of the irradiation position of the laser beam.
  4. A laser head mounted on a radiation therapy apparatus that irradiates radiation from a radiation source traveling on the same spherical surface toward the isocenter that is the center of the spherical surface from multiple directions, and irradiates laser light in the same direction as the radiation,
    A calibration jig for mechanically defining the position of the isocenter,
    Imaging means for horizontally occupying the light receiving surface in the isocenter using this calibration jig,
    Based on a center position of the laser light formed on the imaging surface at a predetermined reference position, a positional shift amount of the center position of the laser light irradiated from any position on the same spherical surface on the imaging surface is detected. An apparatus for evaluating the amount of displacement of a radiation irradiation position, characterized in that:
  5. A frame having an arc-shaped trajectory, a radiation source movably supported along the trajectory, a moving mechanism for moving the radiation source along the trajectory, and the frame so that the trajectory describes a spherical surface. A displacement of a radiation irradiation position in a radiation therapy apparatus for irradiating radiation from a radiation source moving on the same spherical surface to an isocenter which is the center of the spherical surface from multiple directions and having a tilting mechanism for rotating about a tilting axis. A quantity evaluation device,
    A laser head mounted on the frame and irradiating laser light in the same direction as the radiation,
    A calibration jig for mechanically defining the position of the isocenter,
    Imaging means for horizontally occupying the light receiving surface in the isocenter using this calibration jig,
    Based on a center position of the laser light formed on the imaging surface at a predetermined reference position, a positional shift amount of the center position of the laser light irradiated from any position on the same spherical surface on the imaging surface is detected. An apparatus for evaluating the amount of displacement of a radiation irradiation position, characterized in that:
  6. A frame having an arc-shaped trajectory, a radiation source movably supported along the trajectory, a moving mechanism for moving the radiation source along the trajectory, and the frame so that the trajectory describes a spherical surface. A tilting mechanism for rotating about a tilt axis, a first oscillating mechanism for rotating the radiation source about one axis at a specific position on the frame, and the radiation source at a specific position on the frame. And a second swing mechanism for rotating the axis about the other axis different from the one axis, from a radiation source moving on the same spherical surface toward the isocenter which is the center of the spherical surface from multiple directions. An apparatus for evaluating a positional deviation of a radiation irradiation position in a radiation therapy apparatus for irradiation,
    A laser head mounted on the frame and irradiating laser light in the same direction as the radiation,
    A lower end surface of a transmission hole which is formed detachably with respect to the frame and has a center axis of the calibration rod coinciding with the tilt axis when mounted on the frame, and is a through-hole formed in a central portion of the calibration rod. A calibration jig having a calibration rod formed so as to face the isocenter,
    Reflecting means mounted on the upper surface of the calibration rod at the position of the transmission hole to form a horizontal plane,
    The space is fixed to the XYZ stage so that the space can be freely moved and the space position of the space can be known. And imaging means configured so that the imaging surface can be horizontally occupied in a plane including the isocenter,
    Based on a center position of the laser light formed on the imaging surface at a predetermined reference position, a positional shift amount of the center position of the laser light irradiated from any position on the same spherical surface on the imaging surface is detected. An apparatus for evaluating the amount of displacement of a radiation irradiation position, characterized in that:
  7. [Claim 4] In the apparatus for evaluating a displacement of a radiation irradiation position according to any one of claims 4 to 6,
    An apparatus for evaluating a positional deviation of a radiation irradiation position, wherein the laser head is mounted in place of a radiation source and supported so as to be movable along a trajectory of a frame.
  8. [Claim 4] In the apparatus for evaluating a displacement of a radiation irradiation position according to any one of claims 4 to 6,
    The laser head and the radiation source are formed as an integral structure, and the relative position of the reflecting means with respect to the radiation source with respect to the optical axis position of the radiation source is formed so as to be adjustable. An apparatus for reflecting the laser beam by the reflecting means so that an optical axis coincides with an optical axis of the radiation emitted by the radiation source; .
JP2002182619A 2002-06-24 2002-06-24 Method and apparatus for evaluating misalignment of radiation irradiation position Expired - Fee Related JP3905798B2 (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013134597A1 (en) 2012-03-08 2013-09-12 The Johns Hopkins University A method and apparatus for real-time mechanical and dosimetric quality assurance measurements in radiation therapy
CN107941153A (en) * 2017-12-29 2018-04-20 厦门大学 A kind of vision system of laser ranging optimization calibration

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013134597A1 (en) 2012-03-08 2013-09-12 The Johns Hopkins University A method and apparatus for real-time mechanical and dosimetric quality assurance measurements in radiation therapy
CN104204852A (en) * 2012-03-08 2014-12-10 约翰霍普金斯大学 A method and apparatus for real-time mechanical and dosimetric quality assurance measurements in radiation therapy
EP2823333A4 (en) * 2012-03-08 2015-11-04 Univ Johns Hopkins A method and apparatus for real-time mechanical and dosimetric quality assurance measurements in radiation therapy
RU2607079C2 (en) * 2012-03-08 2017-01-10 Дзе Джонс Хопкинс Юниверсити Method and device for mechanical and radiation quality guarantee measurement in real time in radiation therapy
CN107941153A (en) * 2017-12-29 2018-04-20 厦门大学 A kind of vision system of laser ranging optimization calibration

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