JP3825384B2 - Radiotherapy apparatus and method of operating the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a radiation therapy apparatus that moves a radiation generation apparatus along a spherical surface centered at an isocenter and an operation method thereof .
[0002]
[Prior art]
Radiotherapy devices used in the medical field include an isocentric type and a non-isocentric type. An isocentric radiotherapy apparatus includes a gantry that rotates about a horizontal axis as a positioning device. The therapeutic radiation is emitted from the end of the gantry toward the isocenter set on the horizontal axis. A patient who is a subject of radiation therapy is laid on a bed so that the radiation target is located at the isocenter. In addition, the isocentric radiotherapy apparatus rotates the gantry and the bed to change the irradiation direction of the radiation with respect to the irradiation target. By matching the marking on the patient's body surface with the laser beam projected from the laser light source installed in the treatment room, the irradiation target is matched with the isocenter. The marking is applied to the patient's body surface based on a pre-built treatment plan.
[0003]
A non-isocentric radiotherapy apparatus includes an articulated robot arm as a positioning device. The therapeutic radiation is emitted from a radiation generator attached to the tip of the robot arm. This radiotherapy apparatus irradiates therapeutic radiation from multiple directions by arranging a radiation irradiation target within a radiation irradiation range. The patient subject to radiation therapy is laid on a bed and moved by the bed so that the irradiation target is located within the radiation irradiation range. The irradiation object is positioned by matching a marking applied to the patient's body surface with a laser beam projected from a laser light source installed in the treatment room, as in the case of an isocentric radiotherapy apparatus.
[0004]
[Problems to be solved by the invention]
However, the laser light source provided in the treatment room can emit a laser beam only in the direction in which it is installed. Therefore, when the radiation generator is set at a position that blocks the laser beam emitted from the laser light source, the marking for positioning cannot be used effectively. Further, depending on the orientation of the patient, there may be a case where a marking portion to be irradiated with the laser beam has to be provided at a position away from the irradiation target. As a result, the reliability of positioning accuracy decreases.
[0005]
The lesion that is the target site of the positioned radiation is in the body and cannot be confirmed directly. In addition, these radiotherapy apparatuses move and position the patient so that the radiation irradiation target is located at the isocenter. However, the marking drawn on the surface of the body may be misaligned with the irradiation target due to the kinking of the epidermis. For this reason, while moving the patient, the relative position of the marking and the irradiation target may deviate from the treatment plan. In the course of radiation therapy, the patient's body shape may be flattened or moved due to gravity.
[0006]
Therefore, the patient's body may be restrained by a fixture so that the radiation treatment plan is reproduced with respect to the relative positional relationship between the marking and the irradiation target. However, even when restraining with a fixture, the patient cannot be completely fixed, and even if the marking on the body surface can be fixed, the irradiation target in the body cannot be fixed. Therefore, it is difficult to position the irradiation target based on the marking. For this reason, since it is necessary to set the irradiation range in anticipation of the therapeutic radiation deviating from the irradiation target, it is difficult to reduce the radiation dose.
[0007]
Then, an object of this invention is to provide the radiotherapy apparatus which can position the irradiation object of radiation within the radiation irradiation range easily, and its operating method .
[0008]
[Means for Solving the Problems]
A radiotherapy apparatus according to the present invention includes a radiation generating apparatus that emits radiation and a laser beam coaxially, and at least three body surfaces in which a central axis of the radiation indicates a position incident on a patient and an orientation with respect to an irradiation target is set marking and a guide for the arc moves the radiation generator along the radius of the trajectory of the predetermined distance the radiation axis radiation and the laser beam is emitted coaxially around the isocenter so as to intersect at one point, the a support member for rotating the guide about a tilting axis which intersects the rotation axis and the isocenter of the arc moving along the guide of the radiation generating apparatus, a movable member which moves the radiation generator along the guide, the The patient is moved so that the body surface marking corresponding to the laser beam projected from each direction set by using the movable member matches. A slide board to a detector for detecting the information of the fluoroscopic image of a range including an irradiation target of the radiation to be disposed in the vicinity and the isocenter, a plurality of the perspective that the detector detects each of a plurality of orientations group and analyzer, the relative positional relationship for calculating the relative positional relationship between the information of the image and the position of the isocenter based on said orientation information detected fluoroscopic images to the isocenter and a position of the irradiation target characterized in that it comprises a control device for moving the radiation generator to.
[0009]
In this case, a detector detects the radiation radiate | emitted from the radiation generator as information of a fluoroscopic image. Then, the analysis device calculates the relative positional relationship between the isocenter and the irradiation target based on the position information of the radiation generator positioned at a desired position with respect to the isocenter and the information of the fluoroscopic image obtained by the detector. . Further, these detectors are placed in a point-symmetrical position with respect to the radiation generator positioned at a desired position with respect to the isocenter when detecting the information of the fluoroscopic image.
[0010]
Or a detector detects the radiation radiate | emitted from the radiation source provided separately from the radiation generator as information of a fluoroscopic image. And at least 2 pairs of a detector and the radiation source which irradiates the radiation for acquiring the information of a fluoroscopic image toward a detector are provided.
Further, the operation method of the radiotherapy apparatus according to the present invention includes a radiation generator that emits radiation and a laser beam coaxially, a slide board that moves a patient, and an irradiation that emits the radiation and the laser beam coaxially. A guide for moving the radiation generator in an arc along a trajectory having a radius of a predetermined distance around the isocenter so that the axes intersect at one point; a rotation axis of the arc movement along the guide of the radiation generator; and the isocenter a support member for rotating the guide about a tilting axis which intersect at a movable member which moves the radiation generator along the guide, when moving the radiation generator before Kia isocenter and radiation A detector that detects information of a fluoroscopic image in a range including the irradiation target, and a relative positional relationship between the position of the isocenter and the position of the irradiation target An analysis device for calculating, a method of operating a radiation therapy device and a control device for moving the radiation generator based on the relative positional relationship, with the movable member, which is set based on the treatment plan each at least emits a pre SL laser beam with respect to the lesion to be the irradiation target from the orientation of the patient's body surface, the central axis of the radiation direction with respect to the irradiation object indicates a position incident on the patient has been set The slide board is moved so that three body surface markings coincide with the spot of the laser beam, and the fluoroscopic image is detected with respect to the isocenter and information of the fluoroscopic images respectively detected in a plurality of directions by the detector. On the basis of the information of the detected azimuth, the relative position relationship between the position of the isocenter and the position of the irradiation target is calculated by the analysis device, The control device is characterized by moving the radiation generator based on the relative positional relationship.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
A radiotherapy apparatus 1 according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 5. A radiotherapy apparatus 1 shown in FIG. 1 includes a radiation generation apparatus 2, a guide 3, a support member 4, a movable member 5, a detector 6, an analysis apparatus 7, a control apparatus 8, and a bed 9. .
[0012]
The radiation generator 2 emits X-rays R as radiation. The X-rays R are generated by accelerating electrons emitted from the electron gun with an accelerator and colliding with a target. The radiation generator 2 has a built-in laser oscillator and emits a laser beam L coaxial with the X-ray R.
[0013]
The movable member 5 pivotally supports the radiation generating apparatus 2 with two rotation axes C and D that intersect each other. The rotation axes C and D are arranged so as to be orthogonal to the irradiation axis A in which the X-ray R and the laser beam L are coaxially combined. The rotation axis C tilts the radiation generator 2 in the direction of the arrow U, and the rotation axis D tilts the radiation generation apparatus 2 in the direction of the arrow V. Thereby, the radiation generator 2 performs what is called a swing motion.
[0014]
The guide 3 is formed in an arc shape and supports the movable member 5 so as to move along the arc. The guide 3 moves the radiation generating apparatus 2 along a track having a predetermined radius centered on the isocenter 10. The guide 3 has a moving range in which the radiation generating apparatus 2 is moved beyond the range in which the X-ray R is irradiated from the opposite direction with respect to the isocenter 10. That is, the guide 3 can rotate the radiation generator 2 by 180 ° or more around the isocenter 10.
[0015]
The support member 4 rotates the guide around the tilt shaft 11. The tilt axis 11 intersects with the rotation axis 12 on which the radiation generator 2 moves along the guide 3 at the isocenter 10. In this case, it is preferable that the tilting shaft 11 and the rotating shaft 12 are orthogonal to each other from the viewpoint of positioning control of the radiation generator 2. In the radiotherapy apparatus 1 of the present embodiment, since the tilt shaft 11 is disposed horizontally, the guide 3 has a so-called Ω shape. The support members 4 are disposed on both sides along the tilt axis 11 from the isocenter 10 and are fixed to the floor. Further, at least one of the support members 4 that pivotally support the guide 3 is provided with a servo motor 4a as a drive device for tilting the guide 3. The guide 3 is arranged eccentric from the isocenter 10. Therefore, a counterweight may be attached in order to reduce the load on the servo motor 4a by arranging the position of the center of gravity on the tilting shaft 11.
[0016]
The radiation generating apparatus 2 is attached to a movable member 5 that moves about a rotation shaft 12 along a guide, and the guide 3 rotates about a tilting shaft 11, thereby along a spherical surface centered on an isocenter 10. Moving. The isocenter 10 moves the movable member 5 along the guide 3 and rotates the guide 3 around the tilting axis 11 so that the irradiation axis A extending from the radiation generator 2 positioned in different directions intersects at one point. It is.
[0017]
The detector 6 is arranged in a point-symmetrical direction with respect to the radiation generator 2 positioned in an arbitrary direction with respect to the isocenter 10. The detector 6 detects the X-ray R emitted from the radiation generator 2 on the detection surface 6a as information of a fluoroscopic image in a range including the isocenter 10. In this case, the radiation generator 2 passes through the patient P to be subjected to radiation therapy arranged in a range including the isocenter 10 and the slide board 9a of the bed 9 on which the patient P is laid, and a fluoroscopic image of this portion. X-rays R with such a small output as to obtain the above are emitted toward the detector 6. The detector 6 can be changed in position and height according to the direction of the radiation generator 2 and the angle of the irradiation axis A, and is provided so that the detection surface 6a can be tilted. Therefore, the detector 6 can be set so as to detect the X-ray R vertically on the detection surface 6a. In FIG. 1, the radiotherapy apparatus 1 is in a state of irradiating therapeutic X-rays R, and the detector 6 is moved away from the bed 9. Further, the detectors 6 may be moved each time according to the orientation of the radiation generation apparatus 2, or a number corresponding to the preset orientation of the radiation generation apparatus 2 may be arranged.
[0018]
The analysis device 7 includes information on the fluoroscopic images detected in a plurality of directions with respect to the range including the isocenter 10 where the irradiation target 13 of the X-ray R is arranged, and the direction in which each fluoroscopic image is detected with respect to the isocenter 10. In the present embodiment, the relative positional relationship between the isocenter 10 and the irradiation target 13 is calculated based on the position information of the radiation generator 2 in this embodiment. For example, as shown in FIG. 2A, when the irradiation target 13 is shifted with respect to the isocenter 10, the fluoroscopic image g near the isocenter 10 obtained by irradiating the X-ray R from the azimuth G and the azimuth H to X The perspective image h in the vicinity of the isocenter 10 obtained by irradiating the line R differs in the position at which the irradiation target 13 is projected, as shown in FIGS. Accordingly, based on the position coordinates of the azimuth G and H with respect to the isocenter 10 and the fluoroscopic images g and h, the relative positional relationship between the isocenter 10 and the irradiation target 13, that is, the position coordinates of the irradiation target 13 applies the principle of parallax. You can ask for it. Further, the relative three-dimensional positional relationship between the isocenter 10 and the irradiation target 13 can be obtained based on the perspective images of at least two different orientations.
[0019]
The control device 8 controls the guide 3, the support member 4, and the movable member 5 based on the relative positional relationship calculated by the analysis device 7, and automatically sets the setting position of the radiation generator 2 and the angle of the irradiation axis A. To correct. The radiotherapy apparatus 1 is controlled by replacing the coordinate system centered on the isocenter 10 with the coordinate system centered on the irradiation target 13.
[0020]
The bed 9 includes a slide board 9a for laying the patient P to be subjected to radiation therapy, and a drive mechanism 9b for moving the X-ray R irradiation target 13 of the patient P laid on the slide board 9a to the isocenter 10. ing. The slide board 9a is arranged so that the direction perpendicular to the tilt axis 11 is the body axis direction of the patient P.
[0021]
Next, after the treatment plan is made for the irradiation target (lesion) 13 of the patient P to be subjected to radiation therapy and the marking 14 is applied to the body surface of the patient P, the lesion 13 is transferred to the radiation therapy apparatus 1. A method until positioning is described.
[0022]
A plurality of markings 14 are provided on the body surface of the patient P based on the treatment plan. Each marking 14 is set with an orientation with respect to a lesion to be irradiated 13. As shown in FIG. 3, the radiation therapy apparatus 1 aligns the irradiation axis A of the radiation generation apparatus 2 with the orientation set for each marking 14. The slide board 9a of the bed 9 on which the patient P or the patient P is laid is moved so that the marking 14 coincides with the spot of the laser beam L projected onto the body surface of the patient P. In order to determine the relative position of the patient P with respect to the isocenter 10, at least three markings 14 are provided.
[0023]
Next, in order to obtain a fluoroscopic image, the radiation therapy apparatus 1 is arranged at a position corresponding to the direction of the radiation generation apparatus 2 from the radiation generation apparatus 2 positioned in the direction of each marking 14 as shown in FIG. A small output X-ray R is emitted toward the detector 6. Information of the fluoroscopic image detected by the detector 6 corresponding to the radiation generator 2 positioned in each direction is taken into the analysis device 7 together with the position information of the radiation generator 2 corresponding to this fluoroscopic image. Based on these pieces of information, the analysis device 7 calculates the relative positional relationship between the isocenter 10 and the irradiation target 13, that is, the amount of deviation of the irradiation target 13 from the isocenter 10.
[0024]
In addition, what is necessary is just to acquire at least 2 information of a fluoroscopic image. Therefore, first, two fluoroscopic images are acquired, the relative positional relationship is obtained, the irradiation axis A of the radiation generator 2 is corrected based on this, and the irradiation axis A is corrected by the third fluoroscopic image. May be confirmed. Further, even when the detection surface 6a of the detector 6 does not intersect the irradiation axis A at a right angle, correction for the angular deviation of the detection surface 6a is performed from the flatness or extension rate of the fluoroscopic image obtained by the detector 6, It can be handled as information of a fluoroscopic image in a state where the detection surface 6a intersects at right angles to the irradiation axis A. That is, it suffices if the X-ray R emitted from the radiation generator 2 can be detected in order to acquire the information of the fluoroscopic image. Therefore, the position of the detector 6 and the angle of the detection surface 6a need only be approximately matched. The relationship between the information of the transmission image detected by the detector 6 and the position information of the isocenter 10 indicates that the X-ray corresponding to the information capable of positioning the isocenter 10 in the fluoroscopic image is obtained while acquiring the transmission image information. 2 may be output. For example, a filter indicating the position of the isocenter 10 is attached to the emission port of the radiation generator 2, or the irradiation field is narrowed down to the position of the isocenter 10 while maintaining the positional relationship with the detector 6, and X-ray R with a small output is irradiated. You can do it.
[0025]
The deviation amount of the irradiation target 13 with respect to the isocenter 10 is corrected based on the coordinates of the irradiation target 13 calculated by the analyzer 7 with the isocenter 10 as the reference origin. In the present embodiment, a case where the irradiation target 13 is displaced in parallel with the isocenter 10 as illustrated in FIG. 5 will be described as an example. In addition, the positional deviation amount of the irradiation target 13 is exaggerated for the sake of explanation.
[0026]
As shown in FIG. 5, the amount of deviation 15 in the direction along the rotation axis 12 with respect to the isocenter 10 is the rotation 16 of the guide 3 around the tilting axis 11 and the radiation generator 2 around the rotation axis C. Correct by swinging in the U direction. The amount of deviation 17 in the direction along the tilt axis 11 with respect to the isocenter 10 is a movement 18 centered on the rotation axis 12 of the movable member 5 on which the radiation generation apparatus 2 is mounted and a radiation generation apparatus centered on the rotation axis D. Correct by swinging in the V direction of 2. The shift amount 19 in the direction along the irradiation axis A appears as a change in the spread angle of the X-ray R irradiated to the irradiation target 13. When the irradiation target is large, it is necessary to change the size of the irradiation field with a collimator or the like. However, if the irradiation target is a small irradiation target right next to the isocenter 10, there is no difference in the spread angle of the irradiation field. It can respond without.
[0027]
As described above, the radiation therapy apparatus 1 emits the aiming laser beam L coaxially with the X-ray R from the radiation generation apparatus 2. Therefore, the irradiation target 13 can be positioned using this laser beam L. Further, the radiotherapy apparatus 1 uses the X-ray R emitted from the radiation generation apparatus 2 with a small output to detect the information of the fluoroscopic image near the isocenter 10 by the detector 6, and the information of the fluoroscopic image and the generation of the radiation are detected. Based on the positional information of the apparatus 2, the relative positional relationship between the irradiation object 13 and the isocenter 10 is obtained, and the irradiation axis A is corrected without moving the patient P based on this relative positional relationship. That is, the radiotherapy apparatus 1 corrects the coordinate system set in the radiotherapy apparatus 1 and replaces the coordinate system with the irradiation target 13 of the patient P as a reference for positioning. And according to a radiation treatment plan, X-ray R can be irradiated to irradiation object 13 with sufficient accuracy.
[0028]
In addition, even when the patient P is slanted or slanted with respect to the slide board 9a, the coordinate system of the patient P is set from the markings 14 provided on the body surface of the patient P. Then, the radiation therapy apparatus 1 can be controlled so as to supplement the deviation between the coordinate system of the patient P and the coordinate system of the radiation therapy apparatus 1.
[0029]
Further, since the radiation therapy apparatus 1 emits the laser beam L coaxially with the X-ray R from the radiation generator 2, the incident angle of the X-ray R determined for each marking 14 is reproduced using the laser beam L. Then, a simulation based on a so-called radiation treatment plan can be performed. And since the fluoroscopic image can be acquired in the same direction as the direction of irradiating the therapeutic X-ray R, it is possible to confirm again whether or not the region where it is desired to avoid the irradiation of the therapeutic X-ray R overlaps the irradiation field. it can.
[0030]
A radiotherapy apparatus 21 according to a second embodiment of the present invention will be described with reference to FIG. In addition, about the same structure as 1st Embodiment, the same code | symbol is attached | subjected in a figure and the description is abbreviate | omitted.
[0031]
The radiotherapy apparatus 21 shown in FIG. 6 includes two detectors 22 arranged in point symmetry with the radiation generating apparatus 2 positioned in a predetermined orientation with respect to the isocenter 10. These detectors 22 detect a small output X-ray R emitted from the radiation generator 2 in order to acquire a fluoroscopic image near the isocenter 10. The detector 22 is fixed to the floor at a height that does not interfere with the slide board 9 a that has moved toward the isocenter 10. The detection surface 22 a is set at a right angle to the irradiation axis A of the radiation generator 2. The detector 22 is fixed at a predetermined position and detects a fluoroscopic X-ray R having a predetermined orientation with respect to the isocenter 10.
[0032]
Therefore, the radiotherapy apparatus 21 configured as described above can set the analysis apparatus 7 in advance with respect to the azimuth from which the information of the fluoroscopic image is acquired. Therefore, the relative positional relationship between the isocenter 10 and the irradiation target 13. The calculation for obtaining is simplified. Since other configurations and operations thereof are the same as those of the first embodiment, the present embodiment has the same operations and effects as those of the first embodiment.
[0033]
A radiotherapy apparatus 31 according to a third embodiment of the present invention will be described with reference to FIG. In addition, about the same structure as 1st and 2nd embodiment, the same code | symbol is attached | subjected in a figure and the description is abbreviate | omitted.
[0034]
The radiotherapy apparatus 31 shown in FIG. 7 includes an X-ray source 32 as a radiation source prepared separately from the radiation generation apparatus 2 in order to acquire a fluoroscopic image of the therapeutic X-ray irradiation range including the isocenter 10. Yes. The X-ray source 32 is arranged such that the azimuth for emitting X-rays R for obtaining information of a fluoroscopic image with respect to the isocenter 10 is determined in advance. Further, a detector 33 provided in a pair with the X-ray source 32 is disposed at a position symmetrical to the X-ray source 32 with respect to the isocenter 10. The detection surface 33a of the detector 33 is provided in such a direction that X-rays R emitted from the X-ray sources 32 provided in pairs are incident at right angles. Two or more pairs of the X-ray source 32 and the detector 33 may be provided.
[0035]
In the radiotherapy apparatus 31 configured as described above, since the X-ray source 32 for acquiring a fluoroscopic image is provided separately from the radiation generation apparatus 2, it is not necessary to move the radiation generation apparatus 2. In addition, a fluoroscopic image can be acquired simultaneously by the two X-ray sources 32. Therefore, since there is no time lag for acquiring these fluoroscopic images, a more accurate relative positional relationship between the isocenter 10 and the irradiation target 13 can be calculated. Since this other configuration and its operation are the same as those in the first and second embodiments, this embodiment also provides the same operations and effects as those in the first and second embodiments.
[0036]
【The invention's effect】
According to the radiotherapy apparatus and the operation method thereof according to the present invention, the irradiation target is set near the isocenter using the laser beam emitted from the radiation generating apparatus, and the information of the fluoroscopic image near the isocenter is detected by the detector. Based on the orientation information with respect to the isocenter when the detector acquires the information of the fluoroscopic image and the information of the fluoroscopic image, the relative positional relationship between the isocenter and the irradiation target is calculated by the analyzer. Based on the obtained relative positional relationship between the isocenter and the irradiation target, the irradiation axis of the radiation generator can be adjusted to the irradiation target by controlling the guide, the support member, and the movable member. Therefore, the radiation irradiation target can be easily positioned within the radiation irradiation range. In particular, since a laser beam is emitted coaxially with the radiation from the radiation generator, a so-called radiation treatment plan that uses this laser beam to reproduce and confirm the radiation incident angle determined for each body surface marking based on the treatment plan. A simulation based on can be performed. And since a fluoroscopic image can be acquired in the same direction as the direction which irradiates therapeutic radiation, it can confirm again whether the site | part which wants to avoid irradiation of the therapeutic radiation has overlapped with the irradiation field.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a radiation therapy apparatus according to a first embodiment of the present invention.
2A is a diagram schematically illustrating a state in which a relative positional relationship between an isocenter and an irradiation target of the radiotherapy apparatus in FIG. 1 is detected. FIG. (B) is a figure which shows the fluoroscopic image detected with the detector of the azimuth | direction G in (A) of FIG. (C) is a figure which shows the fluoroscopic image detected with the detector of the azimuth | direction H in (A) of FIG.
3 is a perspective view showing a state in which an irradiation target of a patient is positioned at an isocenter using a laser beam in the radiotherapy apparatus of FIG. 1. FIG.
4 is a perspective view showing a state in which a relative positional relationship between an irradiation target of a patient and an isocenter is detected using radiation in the radiotherapy apparatus of FIG. 1. FIG.
5 is a perspective view showing a state in which the radiation generator is corrected as an irradiation target by the control device in the radiotherapy apparatus of FIG. 1. FIG.
FIG. 6 is a perspective view showing a radiation therapy apparatus according to a second embodiment of the present invention.
FIG. 7 is a perspective view showing a radiation therapy apparatus according to a third embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, 21, 31 ... Radiation therapy apparatus 2 ... Radiation generation apparatus 3 ... Guide 4 ... Support member 5 ... Movable member 6,22,33 ... Detector 7 ... Analysis apparatus 8 ... Control apparatus 10 ... Isocenter 11 ... Inclined shaft 13 ... Irradiation target 32 ... X-ray source (radiation source)
A ... irradiation axis C, D ... rotation axis g, h ... fluoroscopic image L ... laser beam R ... X-ray (radiation)

Claims (7)

A radiation generator for emitting radiation and a laser beam coaxially;
At least three body surface markings in which the central axis of the radiation indicates a position incident on the patient and the orientation with respect to the irradiation target is set;
A guide for moving the radiation generating device in an arc along a trajectory having a radius of a predetermined distance around an isocenter so that an irradiation axis on which the radiation and the laser beam are coaxially intersected at one point;
A support member that rotates the guide around a tilt axis that intersects the rotation axis of the arc movement along the guide of the radiation generating apparatus and the isocenter;
A movable member that moves the radiation generating device along the guide;
A slide board for moving the patient so that the body surface marking corresponding to the laser beam projected from each direction set using the movable member matches,
A detector for detecting information of a fluoroscopic image in a range including the isocenter and the irradiation target of radiation disposed in the vicinity of the isocenter;
The relative position between the position of the isocenter and the position of the irradiation target is based on the information of the plurality of fluoroscopic images detected by the detector in a plurality of directions and the information of the direction of detecting the fluoroscopic image with respect to the isocenter. An analysis device for calculating the positional relationship;
A radiotherapy apparatus comprising: a control device that moves the radiation generation device based on the relative positional relationship.   The radiotherapy apparatus according to claim 1, wherein the detector detects radiation emitted from the radiation generation apparatus as information of the fluoroscopic image.   The radiotherapy apparatus according to claim 1, wherein the detector detects radiation emitted from a radiation source provided separately from the radiation generation apparatus as information of the fluoroscopic image.   The radiotherapy according to claim 2, wherein the detector is placed at a point-symmetrical position with respect to the radiation generating apparatus positioned at a desired position with respect to the isocenter when detecting the fluoroscopic image. apparatus.   The analysis device is configured to determine a relative position between the isocenter and the irradiation target based on position information of the radiation generator positioned at a desired position with respect to the isocenter and information on a fluoroscopic image obtained by the detector. The radiotherapy apparatus according to claim 2, wherein the relationship is calculated.   The radiotherapy apparatus according to claim 3, comprising at least two pairs of the detector and a radiation source that irradiates the detector with radiation for acquiring information of a fluoroscopic image. A radiation generator for emitting radiation and a laser beam coaxially; a slide board for moving the patient;
A guide for moving the radiation generating device in an arc along a trajectory having a radius of a predetermined distance around an isocenter so that an irradiation axis on which the radiation and the laser beam are coaxially intersected at one point ;
A support member that rotates the guide around a tilt axis that intersects the rotation axis of the arc movement along the guide of the radiation generating apparatus and the isocenter;
A movable member that moves the radiation generating device along the guide;
A detector for detecting the information in the range of a fluoroscopic image including an irradiation target before Kia isocenter and radiation when moving the radiation generator,
An analyzer for calculating a relative positional relationship between the position of the isocenter and the position of the irradiation target;
A radiotherapy apparatus operating method comprising: a control device that moves the radiation generating device based on the relative positional relationship;
Using said movable member, and to lesions to be the irradiation target from the direction set based on the treatment plan emits a pre SL laser beam,
The slide board so that at least three body surface markings on the patient's body surface where the central axis of the radiation is incident on the patient and whose orientation with respect to the irradiation target is set coincide with the spot of the laser beam Move
Based on information on the plurality of fluoroscopic images detected in a plurality of directions by the detector and information on the orientation in which the fluoroscopic image is detected with respect to the isocenter, the position of the isocenter and the irradiation target are detected by the analysis device. Calculate the relative positional relationship with the position of
An operation method of a radiation therapy apparatus, wherein the radiation generation apparatus is moved based on the relative positional relationship by the control apparatus.

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