JP2007267972A - Radiotherapy apparatus and controlling method of radiotherapy apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiotherapy apparatus which irradiates a diseased site with an appropriate dose of X rays and always orients the irradiation axis of the X rays emitted from a therapeutic X-ray generating source mounted on a gantry to the isocenter where the diseased site to be irradiated is located at an arbitrary gantry travelling angle to reduce the dose of the X rays emitted to the healthy tissues around the diseased site, and a controlling method of the radiotherapy apparatus. <P>SOLUTION: In the radiotherapy apparatus, the therapeutic X-ray generating source is supported by the gantry through a gimbal mechanism for controlling to orient an X-ray axis. A marker member is disposed at an assumed position of the isocenter to identify the isocenter. The position of the marker member in the direction of the height is determined by using laser beams in the horizontal direction as an index, and a horizontal plane containing the isocenter is determined. At the arbitrary gantry travelling angle, X-ray images of the marker member at a plurality of rotation angles are acquired, and the central position is assumed as the position of the isocenter in the horizontal plane. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a radiation therapy apparatus and a control method for the radiation therapy apparatus.

  The X-ray for treatment used in the radiotherapy apparatus is used after the irradiation area is set in accordance with the affected area properties in order to perform an appropriate amount irradiation to the affected area and reduce the irradiation amount to the surrounding healthy tissue. It is necessary to irradiate. For this reason, a treatment plan is drawn up based on the affected area evaluation by CT etc. in advance, and the treatment according to the treatment plan is performed. Specifically, the treatment X-ray generation source is set for the gantry so that the position corresponding to the affected area is located at the isocenter and is also directed to the isocenter. Then, by using a multi-leaf collimator disposed between the therapeutic X-ray generation source and the isocenter, an irradiation region for the affected area of the X-ray irradiated from the therapeutic X-ray generation source is formed into an appropriate property, A predetermined dose of X-ray irradiation is performed.

  For this reason, it is necessary to control the position of the couch on which the patient is placed so that the center of the affected area of the patient is always accurately positioned with respect to the set position of the isocenter. In addition, it is necessary to control the irradiation axis of X-rays irradiated from the therapeutic X-ray generation source so as to always point at the isocenter.

  In particular, the therapeutic X-ray generation unit (therapeutic X-ray generation source, multi-leaf collimator, etc.) mounted on the gantry causes the gantry to be deformed by its own weight (up to several hundred kg), and the traveling angle and turning in the gantry Depending on the angle, a deviation occurs in the relative position between the irradiation axis of the X-rays irradiated from the therapeutic X-ray generation source and the isocenter. In addition, due to wear of mechanical element parts (eg, arbitrary position setting gears) of the radiation therapy apparatus, there may be a time lag in the relative position between the X-ray irradiation axis and the isocenter. Usually, in order to balance the weight of the load with respect to the gantry, a heavy object equivalent to the therapeutic X-ray generator is also placed on the opposite side of the therapeutic X-ray generator mounting position on the gantry (X-ray detector installation part). In this case, the amount of deformation of the gantry due to the weight of both is further increased. For this reason, it is necessary to adjust the X-ray irradiation axis to the isocenter relatively frequently, and a lot of adjustment time is spent for each X-ray irradiation angle based on the treatment plan.

  In relation to the above-described technology, the following proposals have been made.

  In the “X-ray diagnostic apparatus” disclosed in Japanese Patent Application Laid-Open No. 10-337285, an X-ray diagnostic apparatus in which an X-ray generator and an X-ray detector are opposed to each other on an arcuate arm is exposed from the X-ray generator. There is a detection position control means for controlling the X-ray detection position in the X-ray detection unit so that the irradiation field of the emitted X-ray flux matches the image receiving surface of the X-ray detection unit with respect to the irradiation field of the X-ray bundle. X-ray diagnostic apparatuses have been proposed.

  In addition, in the “radiotherapy apparatus” disclosed in Japanese Patent Application Laid-Open No. 2004-97646, a radiation irradiation head that irradiates therapeutic radiation to a treatment field of a subject and a diagnostic X-ray to the treatment field of the subject. And a sensor array that detects diagnostic X-rays transmitted through the subject and outputs them as diagnostic image data. The sensor array moves in conjunction with the movement of the radiation irradiation head. Radiation therapy devices have been proposed.

Japanese Patent Laid-Open No. 10-337285 JP 2004-97646 A

  An object of the present invention is to irradiate an appropriate amount of X-rays to an affected area and reduce the X-ray dose to a healthy tissue around the affected area in order to reduce the amount of X-rays irradiated from a therapeutic X-ray generation source. It is to provide a radiotherapy apparatus capable of always directing an irradiation axis to a predetermined position where an affected area to be irradiated is located, and a method for controlling the radiotherapy apparatus.

  Hereinafter, means for solving the problems will be described using the numbers and symbols used in [Best Mode for Carrying Out the Invention] in parentheses. These numbers and symbols are added to clarify the correspondence between the description of [Claims] and the description of [Best Mode for Carrying Out the Invention]. It should not be used to interpret the technical scope of the invention described in “

  The radiotherapy apparatus (100) of the present invention is rotatable about a first axis passing through the isocenter (200), and is also rotatable about a second axis that intersects the first axis at the isocenter. A gantry (1), an imaging device (6, 16, 190) disposed in the gantry, and a control device (400). The control device captures an image of the marker member by the imaging device from a plurality of positions of a turning angle defined as an angle around the first axis of the gantry. The control device identifies the isocenter identification position based on the visual field position in each of the images.

  In the radiation therapy apparatus (100), the first axis is parallel to the vertical direction. When the control device captures an image of the marker member that is generally disposed at the isocenter position, the control device disposes the imaging device at a position where the gantry and the first axis intersect to capture the image of the marker member.

  In one form of the radiotherapy device (100), the imaging device is the same as the detector (6).

  The radiation therapy apparatus (100) is further disposed on the gantry at a position facing the radiation generation apparatus (2) disposed in the gantry and the radiation generation apparatus via the isocenter, and emitted from the radiation generation apparatus. A detector (6) for detecting the intensity distribution of the generated X-rays, and a gimbal mechanism (3) for adjusting the mounting angle of the radiation generator with respect to the gantry. The control device moves the marker member to an isocenter identification position, and images the image by the imaging device from each of a plurality of travel angles around the second axis of the gantry. For each traveling angle, the amount of adjustment of the gimbal mechanism required for aligning the irradiation axis of the X-rays emitted from the radiation generating device with the position of the marker member is based on the position of the marker member that has been imaged. Ask.

  In one form of the radiotherapy apparatus (100), the imaging apparatus is a CCD camera attached to the X-ray emission end of the radiation generation apparatus so that the center of the visual field coincides with the X-ray irradiation axis. is there. At this time, the marker member is preferably a nylon sphere. Moreover, it is preferable that the marker member is supported by the marker support member on the outer surface.

In the radiotherapy apparatus (100), the CCD camera includes a monochromatic light filter,
In the identification of the isocenter, it is preferable that the marker member is irradiated with monochromatic light having a wavelength capable of transmitting the monochromatic light.

  Said radiotherapy apparatus (100) WHEREIN: In one form, it is preferable that a marker member and the said marker support member differ in a light reflectance. Furthermore, it is more preferable that the marker member has a higher light reflectance than the marker support member.

  In said radiotherapy apparatus (100), it is preferable that a control apparatus performs a binarization process with respect to the image of the imaged marker member.

  In the above radiotherapy apparatus (100), the marker member is larger than the detection limit of the CCD camera and smaller than the visual field range of the CCD camera.

  In the radiation therapy apparatus (100), the marker member has a size of 1/3 to 1/4 with respect to the field of view of the CCD camera.

  In the radiotherapy device (100), the control device stores the adjustment amount of the gimbal mechanism obtained for each traveling angle in association with the traveling angle.

In irradiating the irradiated body with X-rays in the radiotherapy apparatus (100), the control apparatus determines the mounting angle of the radiation generating apparatus based on the relationship between the stored adjustment amount of the gimbal mechanism and the traveling angle. Adjust by mechanism,
After adjusting the mounting angle, the irradiated body is irradiated with X-rays from the radiation generator.

  The radiotherapy apparatus (100) further includes a multi-leaf collimator (8) that cuts a part of the X-rays emitted from the radiation generation apparatus and adjusts the irradiation field, and an attachment position of the radiation generation apparatus with respect to the gantry. An alignment mechanism for adjustment. The imaging device is the same as the detector. The control device evaluates the rotational symmetry of the X-ray intensity distribution for each traveling angle. Based on the evaluation result of the rotational symmetry, an adjustment amount of the alignment mechanism necessary for making the relative arrangement of the multi-leaf collimator and the radiation generating device a desired relationship is obtained. The correspondence relationship between the obtained adjustment amount of the alignment mechanism and the traveling angle is stored.

  In irradiating the irradiated body with X-rays in the radiotherapy apparatus (100), the control apparatus determines the X-ray irradiation axis and the multi-axis on the basis of the correspondence between the stored adjustment amount of the alignment mechanism and the traveling angle. The attachment position of the radiation generator is adjusted so that the relative arrangement with the leaf collimator has a desired relationship. After adjusting the attachment position, X-rays are emitted from the radiation generator to the irradiated object.

  In the radiotherapy device (100), the control device further adjusts the attachment angle of the radiation generator for each traveling angle based on the adjustment amount of the gimbal mechanism obtained for each traveling angle, and attaches the mounting angle. X-rays are emitted in the adjusted state, and an X-ray image of the marker member is captured by the detector. Based on the magnitude of distortion in the X-ray image of the imaged marker member, the amount of angular displacement of the detector with respect to the gantry is obtained. The correlation between the amount of angular displacement of the detector relative to the gantry and the running angle is stored.

  When irradiating an irradiated body with X-rays in the radiotherapy apparatus (100), the control apparatus emits X-rays at a set traveling angle and causes the detector to detect an X-ray image of the irradiated body, The detected X-ray image of the irradiated object is corrected based on the correlation between the amount of angular displacement of the detector attached to the gantry and the traveling angle.

  In the above radiotherapy apparatus (100), the traveling angle is set with respect to each position of a plurality of turning angles defined as an angle around the first axis of the gantry.

  In the above radiotherapy apparatus (100), the control apparatus arranges the radiation generating apparatus at a position where the gantry and the first axis intersect before identifying the isocenter. At each position of the plurality of turning angles, X-rays are emitted from the radiation generator, and the X-ray intensity distribution is detected by the detector. Based on the detection result of the X-ray intensity distribution, the mounting angle of the radiation generating apparatus with respect to the gantry is adjusted so that the X-ray irradiation axis coincides at any turning angle.

  The radiotherapy apparatus (100) further includes a horizontal axis adjusting light source (500) that emits a light beam in the horizontal direction from the height position of the isocenter. Before identifying the isocenter, the control device adjusts the position of the marker member in the height direction using the light beam emitted from the horizontal axis adjustment light source as an index.

  The method for controlling a radiotherapy apparatus according to the present invention is rotatable around a first axis passing through an isocenter, and is also rotatable around a second axis intersecting the first axis at the isocenter. And an imaging device disposed in the gantry. A marker member that indicates an assumed isocenter position is disposed at a position approximately assumed at the isocenter (step S30), and a plurality of swivel angles defined as angles around the first axis of the gantry are substantially An isocenter identification step (steps S70, 80) for imaging the marker member arranged at the position and identifying the position of the isocenter based on the visual field position in each of the captured image of the marker member.

  In the radiotherapy apparatus control method, the first axis is parallel to the vertical direction. In capturing the marker member image in the isocenter identification step, the radiation generating apparatus captures the marker member image from a position where the gantry and the first axis intersect.

In the above radiotherapy apparatus control method, the imaging apparatus is the same as the detector,
In the step of capturing an image of the marker member from each of a plurality of travel angles, the marker member image emits X-rays from the radiation generator, and the X-ray intensity distribution is detected by a detector. Is done.

  In the above radiotherapy apparatus control method, the radiation therapy apparatus is further disposed on the gantry at a position facing the radiation generation apparatus via an isocenter, and a radiation generation apparatus disposed in the gantry. A detector for detecting an intensity distribution of X-rays emitted from the apparatus; and a gimbal mechanism for adjusting a mounting angle of the radiation generating apparatus with respect to the gantry. Further, from the position of the marker member at the position identified in the isocenter identification step (step S100), and the position of each of a plurality of travel angles defined as the angle around the second axis of the gantry, The step of capturing an image of the marker member (step S120), and necessary for aligning the X-ray irradiation axis with the position of the marker member based on the position of the captured marker member for each traveling angle, An adjustment amount determining step (step S130) for obtaining an adjustment amount of the mounting angle of the radiation generating apparatus with respect to the gantry.

  In the above-described radiotherapy apparatus control method, the imaging apparatus is attached to the X-ray emission end of the radiation generation apparatus so that the center of the visual field coincides with the irradiation axis of the X-ray emitted from the radiation generation apparatus. It is a CCD camera.

  The above-described method for controlling the radiation irradiation apparatus further includes a step (step S140) of storing the adjustment amount of the attachment angle obtained for each traveling angle in association with the traveling angle.

  The method for controlling the radiation irradiation apparatus further includes a step of adjusting the mounting angle of the radiation generating apparatus at the set traveling angle based on the relationship between the stored adjustment amount of the mounting angle and the traveling angle, Irradiating an irradiation target with X-rays from the radiation generating apparatus after adjusting the angle.

  In the above-described radiotherapy apparatus control method, the radiotherapy apparatus further includes a multi-leaf collimator that cuts a part of the X-rays emitted from the radiation generation apparatus and adjusts the irradiation field. The imaging device is the same as the detector. For each traveling angle, the step of evaluating the rotational symmetry of the X-ray intensity distribution emitted from the radiation generator (step S150), and based on the evaluation result of the rotational symmetry, the multi-leaf collimator, the X-ray irradiation axis, The step of obtaining the adjustment amount of the attachment position of the radiation generating device with respect to the gantry necessary for making the relative arrangement of the desired positions (steps S120 to S180) and the correspondence between the adjustment amount of the attachment position and the traveling angle are stored. (Step S200).

  The above radiotherapy apparatus control method is such that the X-ray irradiation axis and the multi-leaf collimator have a desired relationship at the set angle based on the correspondence between the stored adjustment amount of the mounting position and the traveling angle. And adjusting the attachment position of the radiation generator, and, after adjusting the attachment position, irradiating the irradiated object with X-rays from the radiation generator.

  The above-described radiotherapy apparatus control method further adjusts the mounting angle by adjusting the mounting angle of the radiation generator for each traveling angle based on the adjustment amount of the mounting angle obtained for each traveling angle. X-rays are emitted in a state and an X-ray image of the marker member is captured by the detector (step S400), and the gantry of the detector is based on the magnitude of distortion of the captured X-ray image of the marker member. And a step (step S500) of storing the correlation between the mounting angle displacement amount of the detector with respect to the gantry and the travel angle (step S600).

  The above radiotherapy apparatus control method further includes the step of taking an X-ray image of the irradiated object at the set traveling angle, and the correlation between the displacement amount of the stored detector relative to the gantry and the traveling angle. Correcting the imaged X-ray image of the irradiated object based on the relationship (step S700).

  In the above radiotherapy apparatus control method (100), the traveling angle is set with respect to each position of a plurality of turning angles defined as an angle around the first axis of the gantry.

  The radiotherapy apparatus control method described above further includes a pre-alignment step (steps S10 and S20) executed before the isocenter identification step. The pre-axis alignment step includes a step of placing the radiation generating device at a position where the gantry and the first axis intersect (Step S10), and X emitted from the radiation generating device from each of a plurality of turning angles. Detecting the intensity distribution of the line, and adjusting the mounting angle of the radiation generator with respect to the gantry so that the X-ray irradiation axis coincides at any turning angle based on the detection result of the X-ray intensity distribution (step) S20)

  The above radiotherapy apparatus control method is further executed before the isocenter identification step, and the isocenter height position is used to adjust the position of the marker member in the height direction using the light beam emitted from the isocenter height position as an index. A setting step (steps S40, 50, 60) is provided.

  According to the present invention, in order to irradiate an appropriate amount of X-rays to the affected area and to reduce the X-ray irradiation amount to the healthy tissue around the affected area, irradiation is performed from a therapeutic X-ray generation source attached to the gantry. It is possible to provide a radiotherapy apparatus capable of directing an X-ray irradiation axis to a predetermined position where an affected area to be irradiated is always located at an arbitrary gantry traveling angle, and a method for controlling the radiotherapy apparatus.

  With reference to the attached drawings, the best mode for carrying out the radiotherapy apparatus and the radiotherapy apparatus control method according to the present invention will be described below.

  FIG. 1 shows a schematic configuration of a radiotherapy apparatus according to an embodiment of the present invention, and FIG. 2 shows a sectional structure thereof. The radiotherapy apparatus 100 according to the present embodiment includes a rotating gantry 1, a therapeutic X-ray generation source 2, a detector (FPD, CCD, MWPC, X-ray film, etc.) 6, and a diagnostic X-ray generation source 5. And a detector 4 and a couch 7 for placing a patient. The therapeutic X-ray generation source 2 has a gimbal structure 3 whose X-ray irradiation axis can be rotated around two axes as needed to control the directivity angle. Furthermore, in the embodiment of the present invention, the therapeutic X-ray generation source 2 and the affected part are used to set the X-ray irradiation region according to the affected part property and to reduce the X-ray irradiation amount to the healthy tissue around the affected part. And a multi-leaf collimator (MLC) 8. A flattening filter for flattening the X-ray intensity distribution may be disposed between the therapeutic X-ray generation source 2 and the multi-leaf collimator 8. Even when the flattening filter is arranged, the X-ray intensity distribution has a slight gradient, and the center of the X-ray intensity can be obtained by the detector. A schematic configuration of the therapeutic X-ray generation source 2 and the multi-leaf collimator (MLC) 8 in the present embodiment is shown in FIG. In the therapeutic X-ray generation source 2, the electron beam 2 b emitted from the electron gun is accelerated while obtaining energy while passing through the electron beam accelerator 2 a, and is mechanically applied to the end of the electron beam accelerator 2 a. It collides with the connected X-ray target 2c. From the X-ray target 2c, X-rays 9 having the same irradiation axis as the electron beam are generated by bremsstrahlung based on the relationship between the electron beam incident direction and the X-ray emission angle distribution. As shown in FIG. 3, the X-ray 9 generated by the X-ray target 2 c is changed according to the affected part property by a multi-leaf collimator (MLC) 8 disposed between the therapeutic X-ray generation source 2 and the affected part. The utilization line cone 10 is formed.

  The radiotherapy apparatus 100 according to the embodiment of the present invention has a control computer as the control apparatus 400. Then, the control computer is used to identify the isocenter and adjust the position of the couch and the irradiation axis of the therapeutic X-ray source 2 at the isocenter based on the isocenter position set by the isocenter identification. The amount is calculated, and the position of the couch and the irradiation axis of the therapeutic X-ray generation source based on the calculated amount are controlled. In the present invention, a marker member for indicating an assumed isocenter position is used for isocenter identification. As the marker member, any member can be used as long as it can be imaged by the detector 6 and its center position can be clearly understood, but a spherical object that can be calibrated from an arbitrary direction is preferable. Metal spheres, nylon spheres, and the like, which have a high sphericity (for example, JIS B1501) and are easy to identify the center shape by means described later, are optimal. Further, the shape dimension is selected according to the detection limit, the detector dimension, and the installation distance.

  In the radiotherapy apparatus of the present invention, the gantry is rotatable about two rotation axes that pass through the isocenter and are substantially orthogonal to each other. One axis is generally oriented in the vertical direction, and this axis is the turning axis. Further, the angle around the turning axis is defined as the turning angle. On the other hand, an axis substantially orthogonal to the turning axis is defined as a traveling axis. The position where the gantry and the turning axis intersect (top or bottom) is defined as a travel angle of 0 ° or ± 180 °. In the description of the embodiments of the present invention, as described above, the swivel axis is described as being oriented in the vertical direction. However, if the swivel axis and the travel axis are substantially orthogonal to each other, the orientation direction of the swivel axis is described. Is not defined vertically. For example, the same holds true even when the turning axis is oriented in the horizontal direction.

  In the present embodiment, (1) the surface defined by the gantry traveling angle ± 90 ° is a horizontal plane including an isocenter, and the horizontal axis adjustment laser (a laser beam that can indicate a horizontal position is not limited to a laser). ) Is used to set the horizontal position of the isocenter by placing a metal ball as a marker member at the optimum position in the horizontal plane. (2) Next, when the therapeutic X-ray generation source 2 is disposed at a position where the gantry travel angle is 0 degree, the metal at a plurality of gantry turning angles is used by using the therapeutic X-ray and the X-ray detector. The spherical coordinates are measured, and the position of the metal sphere in the horizontal plane is adjusted so that the coordinates of the metal sphere are the same at any turning angle (see FIG. 4), and the position is set as the position of the isocenter in the horizontal plane. (3) Further, at an arbitrary gantry traveling angle and turning angle, identification of a required driving amount for the gimbal structure necessary for making the X-ray irradiation axis coincide with the installed metal ball is performed.

  In the radiotherapy apparatus 100 according to the embodiment of the present invention, the isocenter position shown in (1) to (2) is identified by the control apparatus 400, and any radiotherapy apparatus is selected in (3). The relative position between the couch and the isocenter and the relative position between the irradiation axis of the X-rays irradiated from the therapeutic X-ray generation source and the isocenter corresponding to the gantry travel angle and the turning angle are calculated. And by holding the amount of deviation (necessary adjustment amount) with respect to the isocenter of the couch and the X-ray axis based on the respective calculation results as a table, X at various irradiation angles (running angle and turning angle) based on the medical plan Even when X-ray irradiation is required, the affected part located at the isocenter is quickly irradiated with the X-ray irradiation axis. Thus, in order to irradiate the affected area with an appropriate amount of X-rays and reduce the radiation dose to the healthy tissue around the affected area, the X-rays irradiated from the therapeutic X-ray generation source attached to the gantry A radiation therapy system that can always direct the irradiation axis to the isocenter where the affected area to be irradiated is positioned at any gantry traveling angle is realized.

(Embodiment 1) Radiotherapy apparatus FIG. 5 shows a schematic configuration of a radiotherapy apparatus according to Embodiment 1 of the present invention. As shown in FIG. 1 and FIG. 2, the radiotherapy apparatus 100 according to the present embodiment includes a rotating gantry 1 and generation of therapeutic X-rays that are attached to the rotating gantry 1 and emit therapeutic X-rays. Detected with respect to the X-ray irradiation axis in order to detect X-rays that are attached to the source 2 and the therapeutic X-ray generation source 2 of the rotating gantry 1 and that are emitted from the therapeutic X-ray generation source 2 The detector (FPD, CCD, MWPC, X-ray film, etc.) 6 arranged so that the surface is almost vertical, and the position of the affected part (cancer lesion) in the patient's body attached to the rotating gantry 1 A diagnostic X-ray generation source 5 for acquiring a fluoroscopic image for confirmation and a diagnostic X-ray generation source 5 of the rotating gantry 1 that are attached to a position facing the diagnostic X-ray generation source 5 and emitted from the diagnostic X-ray generation source 5 A detector 4 for detecting X-rays; And a couch 7 for placing a person. In the embodiment of the present invention, in order to set an X-ray irradiation region according to the affected part property and to reduce the radiation dose to the healthy tissue around the affected part, the therapeutic X-ray source 2 and the affected part A multi-leaf collimator (MLC) 8 is provided between the two.

  The therapeutic X-ray generation source 2 is attached to the gantry 1 via a support portion 12.

  In the present embodiment, when identifying an isocenter, a metal sphere for indicating an assumed isocenter position is used. The metal sphere is attached to the tip of the sphere support rod, and the sphere support rod is attached to a predetermined position of the couch at the time of isocenter identification.

  As shown in FIG. 5, the radiotherapy apparatus according to the present embodiment further includes a laser apparatus 500 for generating laser light 500a for setting the horizontal position of the horizontal plane in isocenter identification. . In the present embodiment, in order to identify the position of the isocenter in the horizontal plane direction, the X-ray irradiated from the therapeutic radiation apparatus 2 and the detector 6 for detecting the X-ray are used.

  The radiotherapy apparatus 100 according to the present embodiment has a computer (not shown) provided with a CPU and a storage unit. Then, in the storage unit, based on the isocenter identification and the isocenter position set by the isocenter identification in the radiotherapy apparatus according to the embodiment of the present invention, the position of the couch and the irradiation of the therapeutic X-ray generation source A radiotherapy apparatus control program for directing the position of the couch and the irradiation axis of the therapeutic X-ray generation source to the isocenter is calculated in advance based on the calculation of the adjustment amount for positioning the axis at the isocenter and the calculation result. Stored.

(Operation principle of Embodiment 1)
Hereinafter, the operation flow of the present embodiment will be described with reference to FIG. When the radiotherapy apparatus 100 according to the present embodiment is activated, the CPU of the control computer (not shown) provided in the radiotherapy apparatus 100 according to the present embodiment stores the radiotherapy apparatus control program stored in advance in the storage unit. Is read and executed. When the radiotherapy apparatus control program is executed, the CPU performs isocenter identification and isocenter identification set by isocenter identification according to the following procedure in order to irradiate the affected part with an appropriate amount of X-rays. Based on the above, the adjustment amount for positioning the couch position and the irradiation axis of the therapeutic X-ray generation source at the isocenter is calculated.

  First, initial setting of the gantry is performed so that the traveling angle of the therapeutic X-ray generation source 2 attached to the gantry 1 becomes 0 degree (step S10). When a gantry mounted object such as a therapeutic X-ray generation source is installed at a position where the gantry traveling angle is 0 °, the load direction has symmetry, so that the gantry deformation is mainly in the center direction. This means that the central axis of the X-ray emitted from the position does not change significantly with respect to the initial adjustment position over time. Next, the X-ray generation part mounting angle is adjusted so that the centers of the X-ray irradiation fields are substantially equal at a plurality of arbitrary turning angles of the gantry (step S20). Thereby, the turning axis of the gantry and the X-ray irradiation axis are adjusted to be substantially the same. As an arbitrary turning angle, for example, an angle that makes a difference in X-ray image detection sensitivity such as 0 ° or ± 60 ° (0 ° corresponds to a state where the gantry plane is perpendicular to the couch moving direction) may be selected. desirable. Next, a metal ball 150 is installed as a marker member for identifying the isocenter at the isocenter center equivalent position 200 shown in FIG. 5 (step S30). The material of the sphere is not particularly limited to a metal material as long as it has an effective thickness capable of identifying an image by X-ray photography. However, in terms of X-ray transmission characteristics, a metal material is preferable. As will be described later, since the isocenter is identified by imaging the marker member with a detector, the dimension of the sphere can be sufficiently evaluated by the detector in consideration of the resolution and field size of the detector. Set things. The sphere is fixed by a support member. When the sphere has a fitting portion and the support member is fixed so as to be fitted with the sphere, the sphere should be fixed so as not to cause a difference in permeability at the support rod mounting location in the sphere. It is desirable that the X-ray transmission characteristics are not significantly different from those of a sphere. On the other hand, when the support member is attached to the surface of the sphere by bonding or the like, the X-ray transmission characteristics of the support member sphere are different from those of the sphere because of the ease of recognizing the sphere and the support member. It is desirable that Next, the horizontal axis adjustment is performed so that the horizontal height of the laser beam emitted from the horizontal axis adjustment laser device 500 is the same as the gantry traveling angle ± 90 ° plane (plane including the isocenter). The laser device 500 is installed and actually irradiated with laser light (step S40). The position of the metal sphere 150 in the height direction is based on the trajectory of the laser beam 500a emitted from the direction axis adjustment laser device 500, and the gantry traveling angle ± 90 ° plane (plane including the isocenter) is high. To be the same. After the adjustment, it is confirmed whether the position in the height direction of the metal sphere is set to a height based on the laser beam 500a (step S50). If there is an error in the height setting, the metal sphere is again displayed. Reset in the height direction of 150 is performed (step S60), and if it is determined that it is within the specified range, the process proceeds to the next step. When it is confirmed whether the position of the metal sphere in the height direction is set to a height based on the laser beam 500a, the X-ray image of the metal sphere at a plurality of gantry turning angles (see FIGS. 6 and 7). Measurement is performed (step S70). In the measurement of the X-ray image in step S70, an image of the metal sphere 150 at each gantry turning angle is obtained in the X-ray irradiation field 50 as shown in FIG. Based on the position of the metal sphere image, the isocenter center equivalent position in the horizontal plane is calculated (step S80). As an example of the position corresponding to the center of the isocenter, the center of a circle including the respective metal sphere images can be considered as an example (see FIG. 7). Then, it is evaluated whether or not the isocenter center equivalent position calculated in step S80 falls within all allowable ranges as isocenters at the respective turning angles (step S90). If it is determined in step S90 that the isocenter center equivalent position is within the allowable range, it is determined that the position corresponds to the isocenter. On the other hand, if it is determined in step S90 that the isocenter center equivalent position is outside the allowable range, the metal sphere 150 is adjusted to the isocenter center equivalent position based on the evaluation result (step S91).

  When the series of isocenter identification operations described above are completed, the set assumed position of the isocenter is stored in the storage unit of the control computer. Then, based on a predetermined treatment plan, the patient's center of the patient appropriately loaded on the couch and the X-ray irradiation axis of the therapeutic X-ray generation source 2 are moved to the assumed position of the specified isocenter. Thereby, in order to irradiate an appropriate amount of X-rays to the affected area and reduce the X-ray dose to the healthy tissue around the affected area, the X-ray irradiated from the therapeutic X-ray generation source attached to the gantry A radiotherapy apparatus control method that can always direct the irradiation axis of a line to the isocenter where the irradiation target affected part is located is realized.

  In the present embodiment, laser light emitted in a horizontal direction (traveling angle ± 90 °) with respect to the isocenter (the absolute positional accuracy is secured by fixing the laser device itself to a floor surface, for example) The horizontal position of the isocenter can also be set by emitting light from two directions orthogonal to each other in the horizontal plane. Further, a marker is attached to a horizontal plane position passing through a traveling angle of ± 90 ° of the gantry by a laser beam emitted from a laser device placed on the floor or the like, and then the gantry position to which the marker is attached is described above. By continuously mounting the laser device, it is possible to actually reduce the working time by identifying the horizontal position of the isocenter.

  In the present embodiment, the metal sphere used for the X-ray central axis adjustment at each gantry traveling angle is used only by using the position adjustment method using each component requirement and function originally provided in the radiotherapy apparatus. It can be accurately installed at a position corresponding to the isocenter, and the isocenter can be identified at a low cost and in a short time. In the radiotherapy apparatus and the radiotherapy apparatus control method according to this embodiment, as described above, the position where the gantry itself is not easily affected by the deformation (the therapeutic X-ray generation source is disposed at a gantry travel angle of 0 °). ), Isocenter identification is performed, so that parameters to be considered in identification can be reduced, and identification can be performed in a short time.

(Embodiment 2) Radiation therapy apparatus The schematic structure of the radiation therapy apparatus concerning Embodiment 2 of this invention is shown in FIG. The basic configuration of the radiotherapy apparatus according to the present embodiment is the same as that of the first embodiment.

  As shown in FIG. 9, the X-ray irradiation in the actual radiotherapy apparatus is not limited to the travel angle = 0 °, but is arbitrarily traveled and turned as the position of the therapeutic X-ray generation source 2 disposed with respect to the gantry. Done at an angle. At this time, the gantry is deformed by the dead weight of the therapeutic X-ray generation source 2. Therefore, in practice, isocenter identification work considering the above-described gantry deformation and pointing control of the X-ray irradiation axis to the isocenter are desired.

  In the radiotherapy apparatus according to the present embodiment, the gimbal structure 3 is provided between the therapeutic X-ray generation source 2 and the support part 12, and the therapeutic X-ray generation source 2 is arranged in two axes as necessary. And the directivity angle of the X-ray irradiation axis can be controlled.

(Operation Principle of Embodiment 2)
The basic configuration of the operation flow of the present embodiment is the same as that of the first embodiment. However, in the radiotherapy apparatus control method according to the present embodiment, the following steps are added after the isocenter is identified by the operation up to step S90, and the treatment X in the case of an arbitrary gantry traveling angle and turning angle is added. Adjustment of the X-ray irradiation axis of the radiation source 2 is performed. With respect to the assumed isocenter position set in this way, directivity control of the X-ray irradiation axis of the therapeutic X-ray generation source 2 is performed at any turning angle and traveling angle.

  Hereinafter, the operation flow of the present embodiment will be described with reference to FIG. Since the operation up to step S90 is the same as that of the first embodiment, the description thereof is omitted. When the Hose line therapy apparatus according to the present embodiment is activated, a CPU of a control computer (not shown) reads and executes a radiotherapy apparatus control program stored in advance in the storage unit. The radiotherapy apparatus operates as follows according to the radiotherapy apparatus control program.

  A metal sphere is placed at the position of the isocenter identified by the processing up to step S90 (step S100). A running angle and a turning angle to be measured are set (step S110). The position of the therapeutic X-ray generation source 2 is moved to each traveling angle of each turning angle on the gantry. And X-ray | X_line is irradiated for every running angle of each turning angle (step S120). A model in which the therapeutic X-ray generation source 2 is located at the gantry travel angle Φ is shown in FIG. 11A. At this time, the gantry is deformed by the dead weight of the therapeutic X-ray generation source 2, thereby causing a deviation (Δx, Δy) between the isocenter center equivalent position 200 and the X-ray irradiation axis. Further, if the distance between the therapeutic X-ray generation source 2 and the detector 6 is L, for example, from the relationship shown in FIG. 11A (d), Δx on the detection surface of the detector 6 is Δx = L × tan θ. It becomes. In the present embodiment, the position where the X-ray intensity is highest on the detection surface (the position where the X-ray central axis and the X-ray detector incident surface intersect) and the center position of the metal sphere image on the detection surface. Then, the difference between the two at the travel angle is obtained.

For example, as shown in FIG. 11B, when only the generation point source of the therapeutic X-ray generation source is deformed, the irradiation position deviation amount on the X-ray detector when the X-ray emission angle Θ is changed is

Here, since L is known, the current change amount Θ can be recognized by ΔX measurement. On the other hand, in the X-ray detector 6, when the incident surface changes Ψ, the irradiation position deviation amount is

Here, L is known, but Ψ is unknown, and Θ cannot be determined from ΔXX. However, in the case where an inclination that does not change the center positions assumed here is generated, Θ can be identified from the evaluation of L and ΔXX as follows. That is, when the balance between the therapeutic X-ray generation source side and the X-ray detector side is not balanced, Ψ is negligibly small (Ψ≈0). For this reason, since sinΨ≈0 and cosΨ≈1,

On the other hand, when balancing the therapeutic X-ray generation source side and the X-ray detector side, Ψ≈Θ. For this reason,

  Here, only the X direction (one direction in the orthogonal coordinates on the X-ray detector surface) has been described as an object, but the present concept is adjusted to an arbitrary direction by extending it to a two-dimensional plane including the Y direction. be able to.

  In order to make the position where the X-ray intensity obtained as described above becomes highest (the position where the X-ray central axis 2d intersects the X-ray detector incident surface) coincide with the center position of the metal sphere image on the detection surface. X-ray generation unit installation angle adjustment amount (Δx, Δy) necessary for the calculation is calculated for each turning angle and each traveling angle (step S130).

  When the series of operations described above are completed, the calculated X-ray generation unit installation angle adjustment amount is stored in the storage unit of the control computer in association with the turning angle and the traveling angle (step S140).

  In S130, after calculating the X-ray generation unit installation attachment angle adjustment amount, the X-ray generation unit installation angle adjustment amount is actually adjusted by the calculated adjustment amount angle, and then X-rays are irradiated again. It may be confirmed whether the intensity distribution center and the metal sphere image actually match with the angle adjustment amount. In this case, if the calculated angle adjustment amount still causes an error, the attachment angle is finely adjusted. In S140, the adjustment amount until the intensity distribution center and the metal sphere image actually coincide is stored.

  The following steps are operations when actually irradiating the irradiated object with X-rays. When irradiating the irradiated body with X-rays, a turning angle and a traveling angle for irradiating the irradiated body with X-rays are set. After the therapeutic X-ray generation source 2 is arranged at the turning angle and the traveling angle, the X-ray irradiation axis of the therapeutic X-ray generation source 2 is defined based on the stored X-ray generation unit installation angle adjustment amount. The mounting angle is adjusted to face the assumed isocenter position. Then, with the attachment angle adjusted, an appropriate amount of X-rays is irradiated to the affected area. Thus, in order to reduce the amount of X-ray irradiation to the healthy tissue around the affected area, the X-ray irradiation axis irradiated from the therapeutic X-ray generation source attached to the gantry is always set to the position of the affected area. The control method of the radiotherapy apparatus which can be directed to the assumed isocenter position is realized.

  In the present embodiment, by having the gimbal structure 3, it is possible to identify an isocenter that accurately corresponds to the therapeutic X-ray generation source 2 arranged at an arbitrary traveling angle and turning angle. Even when the therapeutic X-ray generation source is positioned at an arbitrary traveling angle and turning angle on the gantry, the X-ray irradiation axis can be always accurately directed to the assumed isocenter assumed position. .

(Embodiment 3)
Embodiment 3 of the present invention will be described. The basic configuration of the radiotherapy apparatus according to the present embodiment is the same as that of the first embodiment. However, the therapeutic X-ray generation source 2 is attached to the support 12 via an alignment mechanism (not shown) so that the relative position with respect to the gantry can be adjusted. The adjustment of the relative position with respect to the gantry means that the position can be moved with respect to the tangential direction of the gantry.

(Operational principle of Embodiment 3)
The basic configuration of the operation flow of the present embodiment is the same as that of the first embodiment. However, in the method for controlling the radiotherapy apparatus according to the present embodiment, an operation after the isocenter is identified by the operations up to step S90 is added. The relative position of the therapeutic X-ray generation source 2 with respect to the gantry is adjusted even when the traveling angle and the turning angle are arbitrary. Thereby, the relative arrangement of the X-ray irradiation axis of the therapeutic X-ray generation source 2 and the multi-leaf collimator can be set to a desired one regardless of the turning angle or the traveling angle.

  With reference to FIG. 17, the operation method according to the present embodiment will be described in detail. Since the operation up to step S90 is the same as that of the first embodiment, the description thereof is omitted. First, a metal ball is placed at the position of the isocenter identified by the operation up to step S90 (step S100). A running angle and a turning angle to be measured are set (step S110). The position of the therapeutic X-ray generation source 2 is moved to each traveling angle of each turning angle on the gantry. And operation | movement of the following step S120-180 is performed for every traveling angle of each turning angle. First, X-rays are irradiated (step S120). It is evaluated whether or not the rotational symmetry of the obtained X-ray intensity distribution is within an allowable range (step S150). If the rotational symmetry is outside the allowable range, the gimbal mechanism is driven to adjust the mounting angle of the therapeutic X-ray generation source 2 with respect to the gantry (step S160). After the attachment angle is adjusted, the process returns to step S120 again, and imaging of the metal sphere is performed. On the other hand, if the rotational symmetry is within the allowable range in step S150, it is evaluated whether or not the position of the center of the metal sphere coincides with the center of the X-ray intensity distribution in the captured X-ray image. Is performed (step S170). When the positions of the center of the metal sphere and the center of the X-ray intensity distribution do not coincide with each other, the position where the therapeutic X-ray generation source 2 is attached to the gantry is adjusted by the alignment mechanism (step S180). After the attachment position is adjusted, the process returns to step S120 again, and the subsequent operations are repeated. On the other hand, if the center of the metal sphere coincides with the center of the X-ray intensity distribution in step S170, the therapeutic X-ray generation source 2 is moved to the travel angle and turning angle to be measured next (step S190). The operations from step S120 to step S180 are repeated. At each turning angle and each traveling angle, the rotational symmetry is within an allowable range, and the driving amounts of the gimbal mechanism and the alignment mechanism until the center of the metal sphere coincides with the X-ray intensity center are This is an adjustment amount for performing proper irradiation to the isocenter at the traveling angle. The correlation between the adjustment amount of the gimbal mechanism and the alignment mechanism, the turning angle, and the traveling angle is stored in the storage unit of the control computer (step S200).

  When actually irradiating the irradiated body with X-rays, the amount of adjustment of the stored gimbal mechanism and alignment mechanism at the turning angle and traveling angle set for irradiating the irradiated body with X-rays The attachment position and angle of the therapeutic X-ray generation source 2 are adjusted based on the relationship. And an X-ray is irradiated with respect to a to-be-irradiated body.

  As described above, the X-rays emitted from the therapeutic X-ray generation source 2 are irradiated to the irradiated object after the irradiation field is adjusted by the multi-leaf collimator. Here, when the relative positional relationship between the X-ray irradiation axis and the multi-leaf collimator is a relationship deviating from the desired relationship, the X-ray irradiation field is not properly adjusted, and the actual It becomes difficult to perform irradiation according to the treatment plan. According to the present embodiment, the relative arrangement of the X-ray irradiation axis and the multi-leaf collimator can be adjusted by adjusting the attachment position of the therapeutic X-ray generation source 2 by the alignment mechanism. it can. Since the rotational symmetry of the X-ray intensity distribution is evaluated and the gimbal mechanism and alignment mechanism are adjusted based on the evaluation results, the arrangement of the X-ray irradiation axis and the multi-leaf collimator should be in a desired relationship. Can do. By storing the adjustment amount of the alignment mechanism obtained for each turning angle and each traveling angle, any turning angle and traveling angle (the turning when actually irradiating the irradiated object with X-rays) (Angle, travel angle), the attachment position and the attachment angle of the therapeutic X-ray generation source can be adjusted based on the stored adjustment amount. Therefore, X-ray irradiation can be performed on the irradiated object in a state where the arrangement of the X-ray irradiation axis and the multi-leaf collimator is in a desired relationship.

(Embodiment 4) Radiotherapy apparatus FIG. 12 shows a schematic configuration of a radiotherapy apparatus according to Embodiment 4 of the present invention. The basic configuration of the radiotherapy apparatus according to this embodiment is the same as that of Embodiments 1 to 3. However, the radiotherapy apparatus according to the present embodiment includes a CCD camera 160 at the X-ray emission end of the therapeutic X-ray generation source 2. The CCD camera 160 is attached to the X-ray emission end of the therapeutic X-ray generation source 2 so that the center of the visual field of the CCD camera 160 coincides with the X-ray irradiation axis of the therapeutic X-ray generation source 2. . In the present embodiment, at the time of isocenter identification, a visible image of a metal sphere acquired by a CCD camera is used without using an X-ray metal sphere image detected by the detector 6.

  In this embodiment, since the visible image of the metal sphere acquired by the CCD camera 160 is used, the position of the metal sphere is known with higher accuracy than the metal sphere image detected by the X-ray detector 6. I can do it. Then, it is possible to set an isocenter position with higher accuracy than isocenter identification using X-rays. Thereby, in the present embodiment, the X-ray irradiation axis can be oriented in the desired X-ray irradiation direction with higher accuracy than in the first and second embodiments. And the stereotactic treatment according to a treatment plan can be reliably performed in arbitrary irradiation angles.

  In addition, it is effective that the present embodiment further includes means for irradiating the marker member with illumination light. With the addition of this configuration requirement, the reflected light intensity from the metal sphere can be secured at a predetermined value or more, so that the detection accuracy can be improved. Furthermore, as shown in FIG. 13, in addition to the CCD camera 160 provided at the X-ray emission end of the therapeutic X-ray generation source 2, a monochromatic illumination device 300 such as an LED may be further provided. At this time, a band pass filter 180 that transmits only monochromatic light emitted from the monochromatic illumination device 300 is attached to the CCD camera 160 via the lens 170. With the CCD camera 160, a metal sphere image composed only of monochromatic light reflected by the metal sphere can be acquired, and the metal sphere and the background image can be more clearly identified. As a result, the difficulty in separating the isocenter 200 from the background in the camera field of view (see FIG. 14), which has been a problem in the past, can be solved, and the alignment accuracy of the metal sphere 150 with respect to the isocenter 200 can be further improved. In the present embodiment, the material of the marker member may be a nylon sphere. This is for the purpose of performing an evaluation based on the marker shape image in the present embodiment, and does not perform an evaluation based on a difference in non-transparency as in the case of using X-rays, and is easy to process. This is because it is advantageous in that the reflection angle dependency is relatively relaxed because multiple scattered light is detected from the inside of the marker. In the lens system provided in the CCD camera, it is desirable to adjust so that the sphere corresponds to 1/3 to 1/4 with respect to the field of view. This is because it is possible to avoid the CCD from being out of the field of view as the detection accuracy increases and the position of the sphere is adjusted. Therefore, it is desirable to adjust the lens strength so that the visual field range can be satisfied at the time of adjustment at a plurality of turning angles after the lens strength is lowered and the visual field is widened at the initial rough setting of the sphere. . Furthermore, it is also effective to apply a paint having a high reflection coefficient to the surface of the marker member. By this correspondence, marker identification can be performed with higher accuracy. At this time, it is further desirable for this purpose to apply a coating material having a low reflectance to the support member of the marker. Furthermore, it is also effective to binarize the reflected light from the marker on the image captured by the CCD camera. This correspondence makes it possible to recognize the marker shape more accurately, and the position with higher accuracy. You will be able to combine.

(Operation Principle of Embodiment 4)
The basic operation principle of this embodiment is the same as that of each of the first to third embodiments. However, in this embodiment, before and after isocenter identification, the center of the visual field of the CCD camera 160 and the X-ray irradiation of the therapeutic X-ray generation source 2 are applied to the X-ray emission end of the therapeutic X-ray generation source 2. A step of attaching or removing the CCD camera 160 is added so that the axis coincides. Further, depending on the setting accuracy of isocenter identification, a step of attaching a monochromatic illumination device 300 such as an LED to the gantry is further added. However, the monochromatic illumination device 300 may be attached to the gantry only during isocenter identification. It may be good or always attached. The position resolution of the detector is generally higher for a visible camera than for an X-ray detector. For this reason, based on this implementation, isocenter identification can be performed with higher accuracy.
In addition, by performing binarization processing on the image captured by the visible camera, it is possible to reduce the influence of the reflection angle dependency of the reflected light from the marker. As a result, for example, when a spherical marker is used, the captured image can be evaluated as an image closer to a perfect circle, so that isocenter identification with higher accuracy can be performed.

  According to the present embodiment, in addition to the operational effects of the first to third embodiments, it is possible to perform isocenter identification with higher accuracy, and thereby, in the X-ray irradiation direction based on the treatment plan, the therapeutic X-ray generation source 2 X-ray irradiation axes can be directed with extremely high accuracy.

(Embodiment 5) Radiotherapy apparatus FIG. 15 shows a schematic configuration of a radiotherapy system according to Embodiment 5 of the present invention. In the stereotactic radiotherapy apparatus 100 according to the present embodiment, in addition to the operations of the first to fourth embodiments, the control apparatus 400 performs an appropriate amount for the affected part located at the isocenter according to a predetermined treatment plan. In order to reduce the amount of X-ray irradiation to the affected tissue around the affected area, the X-ray irradiation axis of the radiotherapy apparatus is controlled so as to accurately irradiate only the affected position. To work.

  The control device 400 in the present embodiment includes a CPU 400d, a storage unit 400e, an input unit 400c for inputting instructions, and a communication unit 400b, each connected to the bus line 400a. The storage unit 400e moves the couch position and the irradiation axis of the therapeutic X-ray generation source to the assumed isocenter position based on the isocenter identification in the radiotherapy apparatus and the estimated isocenter position set by the isocenter identification. The radiotherapy apparatus control program for controlling the irradiation dose based on the calculation of the adjustment amount and the preset treatment plan is stored in advance. Further, the storage unit 400e has adjustment amounts for moving the couch position and the irradiation axis of the therapeutic X-ray generation source to the assumed isocenter position calculated based on the set assumed isocenter position, respectively. A control table 400g listed as a function of the traveling angle and turning angle of the X-ray generation source is stored.

(Operational principle of Embodiment 5)
The operation principle of the radiation therapy apparatus 100 according to this embodiment will be described with reference to FIG. When the radiotherapy apparatus 100 according to the present embodiment is activated, the CPU 400d of the control device 400 is stored in the storage unit 400e in advance, as in any one of the first to third embodiments. The radiotherapy apparatus control program 400f is read and executed. In the storage unit 400e, the adjustment amount for moving the couch position and the irradiation axis of the therapeutic X-ray generation source to the estimated isocenter position calculated based on the set estimated isocenter position is used for the treatment. The amount of adjustment in the traveling angle and the turning angle of the therapeutic X-ray generation source, which is stored as a control table 400g listed as a function of the traveling angle and the turning angle of the X-ray generation source, It is created by interpolating the adjustment amounts for the travel angle and the turning angle that are actually acquired. As a result, the various amounts are adjusted based on the adjustment amount under an arbitrary angle condition. Note that it is desirable to update the control table every elapse of a certain period in order to compensate for the gantry deformation over time.

  In the present embodiment, an image in which a signal having X-ray property information sent from the detector 6 provided in the radiotherapy apparatus is integrated as an external function of the control apparatus 400 or an internal function of the control apparatus 400. It is sent to the comparison device 700. The image comparison apparatus 700 uses the multi-leaf collimator 8 provided in the emission unit of the therapeutic X-ray generation source 2 based on the irradiation area of the affected part determined by a predetermined treatment plan and the X-ray property information. The arrangement position of each leaf provided in the multi-leaf collimator for setting the opening shape is calculated. The calculation result performed by the image comparison device 700 is stored in the storage unit 400e via the communication unit 400b. The CPU 400d controls the position of the couch and the gimbal structure 3 based on the instruction from the input unit c or the treatment plan inputted in advance, and sets the affected part center and the X-ray irradiation axis to the set isocenters, respectively. Move to the expected position. At this time, the CPU 400d refers to the control table 400g in order to direct the X-ray irradiation axis to the irradiation angle based on the treatment plan, and the traveling angle driving unit and the turning angle driving unit of the couch are referred to. / Send the turning angle setting signal. Further, an X-ray generation unit installation angle control signal and an X-ray generation unit installation position control signal are transmitted to the gimbal structure 3 that supports the therapeutic X-ray generation source 2 with respect to the support base 12.

  In the present embodiment, by referring to the control table 400g, the X-ray irradiation axis of the therapeutic X-ray generation source 2 can be accurately and quickly oriented in the X-ray irradiation direction based on the treatment plan. . And the stereotaxic treatment according to a treatment plan can be reliably performed also in arbitrary irradiation angles.

  Here, the control table 400g in the present embodiment is updated every elapse of a certain period or more, and is not affected by the secular change of the system structure including the gantry 1 and the support base 12.

(Sixth Embodiment) Radiation Therapy Device FIG. 16 shows a schematic configuration of a radiation therapy device according to a sixth embodiment of the present invention. The basic configuration of the radiotherapy apparatus according to the present embodiment is the same as that of the fifth embodiment. However, in the present embodiment, in consideration of the amount of angular displacement of the detector with respect to the gantry that occurs when the therapeutic X-ray generation source 2 is positioned at an arbitrary gantry travel angle and swivel angle, Image processing is performed on the line image.

  For this reason, in this embodiment, the X-ray irradiation axis is directed to the isocenter based on the correction amount indicated in the control table 400g acquired in the fourth embodiment, and the X-ray is irradiated in each posture. Based on the detected distortion amount from the circle of the X-ray image of the metal sphere 150, the amount of angular displacement of the detector 6 relative to the gantry is calculated, and the X-ray image of the metal sphere is corrected based on the calculation result. The storage unit 400e is provided with a radiotherapy apparatus control program for executing image processing for the purpose. The finally obtained correction amount as a function of each gantry traveling angle and gantry turning angle may be tabulated and stored in the storage unit 400e.

  In the present embodiment, taking the amount of angular displacement of the detector 6 relative to the gantry into consideration, the image processing for correcting the X-ray image of the metal sphere is executed, so that the collected data before and after radiation irradiation to the affected area is obtained. As a result, the irradiation position accuracy in radiation therapy is improved.

  In this embodiment, a correction device for correcting the mounting angle of the detector 6 with respect to the gantry 1 is provided between the gantry 1 and the detector 6 to correct the mounting angle displacement of the detector with respect to the gantry. Also good.

(Operation Principle of Embodiment 6)
The basic operation principle of the radiotherapy apparatus according to this embodiment is the same as that shown in the fifth embodiment. However, the present embodiment includes the following steps in addition to the step of storing the control table 400g in the storage unit 400e after the isocenter identification described in the fourth embodiment is completed.

FIG. 18 shows an operation flow according to the present embodiment. Note that the steps up to storing the control table 400g are the same as those in the fifth embodiment, and a description thereof will be omitted. First, based on the X-ray central axis adjustment conditions (X-ray generation unit installation angle, etc.) shown in the control table 400g, the X-ray irradiation axis is adjusted for each travel angle (θ) to produce X-rays. The light is emitted (step S400). Based on the metal sphere image acquired in step S400, the major axis diameter (ΔX1) and the minor axis diameter (ΔY1) of the metal sphere image are obtained. Then, based on the obtained major axis diameter (ΔX1) and minor axis diameter (ΔY1) of the metal sphere image, the mounting angle change amount ψ between the X-ray central axis and the detection surface of the detector is expressed as ψ = Cos ⁻¹ ( ΔY1 / ΔX1) is calculated (see step S500, FIG. 16). And the correlation of the said attachment angle variation | change_quantity in each driving | running | working angle ((theta)) is tabulated and stored in a memory | storage part (step S600).

  Then, when an image of the irradiated object is captured, image processing for correcting the captured X-ray image is executed based on the attachment angle change amount shown in the table created in advance in step S600. (Step S700).

  In the radiotherapy apparatus according to the present embodiment, in addition to performing apparatus-side calibration called MLC aperture shape confirmation by the detector 6, data collection is performed in a treatment action such as measurement of an affected part fluoroscopic image during treatment. For this reason, each evaluation content is influenced by the mounting angular displacement between the X-ray central axis and the detection surface of the detector. In this embodiment, the correlation between the running angle and the X-ray detector mounting angle is grasped by a simple method of using the original system configuration as it is, and the evaluation is performed by the X-ray detector based on this value. The influence can be corrected by applying correction (image processing) to the image. As a result, the collected data before and after the treatment action can be appropriately processed, and as a result, the accuracy of the treatment action is improved.

It is a figure which shows schematic structure of the radiotherapy apparatus concerning embodiment of this invention. It is a figure which shows the cross section of the radiotherapy apparatus concerning embodiment of this invention. It is a figure which shows schematic structure of the X-ray generation source for treatment of the radiotherapy apparatus concerning embodiment of this invention, and a multileaf collimator. In the radiotherapy apparatus concerning embodiment of this invention, it is a figure which shows the model which aligns the irradiation axis | shaft of a therapeutic X-ray to an isocenter. In the radiotherapy apparatus concerning Embodiment 1 of this invention, it is a figure which shows the model which aligns the irradiation axis | shaft of a therapeutic X-ray to an isocenter. In the radiotherapy apparatus concerning Embodiment 1 of this invention, it is a figure which shows the model which aligns the irradiation axis | shaft of a therapeutic X-ray to an isocenter. In the radiotherapy apparatus concerning Embodiment 1 of this invention, it is a figure which shows the model which aligns the irradiation axis | shaft of a therapeutic X-ray to an isocenter. In the radiotherapy apparatus concerning Embodiment 1 of this invention, it is a figure which shows the operation | movement flow (radiotherapy apparatus control method) which aligns the irradiation axis | shaft of a therapeutic X-ray to an isocenter. It is a schematic diagram which shows a deformation | transformation of a gantry when the X-ray generation source for treatment of the radiotherapy apparatus concerning Embodiment 2 of this invention is arrange | positioned with arbitrary travel angles. In the radiotherapy apparatus concerning Embodiment 2 of this invention, it is a figure which shows the operation | movement flow (radiotherapy apparatus control method) which aligns the irradiation axis | shaft of a therapeutic X-ray to an isocenter. It is a figure which shows the deviation | shift amount of the isocenter on a detector, and an X-ray central axis when the X-ray generation source for treatment of the radiotherapy apparatus concerning Embodiment 2 of this invention is arrange | positioned with the running angle (theta). FIG. 11A is a diagram showing a deviation amount between the isocenter on the detector and the X-ray central axis when the detection surface of the detector further changes by ψ in FIG. 11A. It is a figure which shows schematic structure of the radiotherapy apparatus concerning Embodiment 4 of this invention. In the radiotherapy apparatus concerning Embodiment 4 of this invention, it is a figure which shows the model which aligns the irradiation axis | shaft of a therapeutic X-ray to an isocenter further using the light source of a monochromatic illumination system. In the radiotherapy apparatus concerning Embodiment 4 of this invention, it is a figure for demonstrating the subject at the time of aligning the irradiation axis | shaft of a therapeutic X-ray to an isocenter, without using the light source of a monochromatic illumination system. It is a figure which shows schematic structure of the radiotherapy system concerning Embodiment 5 of this invention. In the radiotherapy system concerning Embodiment 6 of this invention, it is a figure which shows the model which moves the irradiation axis | shaft of a therapeutic X-ray to an isocenter assumption position. It is an operation | movement flow of Embodiment 3 of this invention. It is an operation | movement flow of Embodiment 6 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Rotating gantry 2 ... Treatment X-ray source 2a ... Electron beam accelerator 2b ... Electron beam 2c ... X-ray target 2d ... X-ray axis 3 ... Gimbal structure 4 ... Detector 5 ... X-ray source 6 for diagnosis ( X-ray) detector 7 ... couch 8 ... multi-leaf collimator (MLC)
DESCRIPTION OF SYMBOLS 9 ... X-ray 10 ... Use line cone 12 ... Support stand 14 ... Collimator 50 ... X-ray irradiation field 60 ... Circle 100 calculated | required from metal ball position ... Radiation therapy apparatus 150 ... Metal ball 160, 190 ... CCD camera 170 ... Lens 180 ... filter 200 ... isocenter 300 ... monochromatic illumination device 400 ... control device 400a ... bus line 400b ... communication unit 400c ... input unit 400d ... CPU
400e ... Storage unit 400f ... Radiation therapy device control program 400g ... Control table 500 ... Laser device 500a ... Laser beam 600 ... Mirror 700 ... Image comparison device 1000 ... Radiation therapy system

Claims (39)

A gantry rotatable about a first axis passing through the isocenter, and also rotatable about a second axis intersecting the first axis at the isocenter;
An imaging device disposed in the gantry;
A control device;
Comprising
The control device captures an image of a marker member by the imaging device from a plurality of positions of a turning angle defined as an angle around the first axis of the gantry,
The said control apparatus is a radiotherapy apparatus which identifies the said isocenter identification position based on the visual field position in each of the said image. The radiotherapy apparatus according to claim 1,
The radiotherapy apparatus in which the first axis is parallel to the vertical direction. The radiotherapy apparatus according to claim 2,
The control device captures the image in a state where the imaging device is disposed at a position where the first axis and the gantry intersect when the image of the marker member disposed at a substantially isocenter position is captured. Radiotherapy device. The radiotherapy apparatus according to any one of claims 1 to 3,
Furthermore,
A radiation generator disposed in the gantry;
A detector that is disposed on the gantry at a position facing the radiation generator via an isocenter and detects an intensity distribution of X-rays emitted from the radiation generator;
A gimbal mechanism for adjusting the mounting angle of the radiation generator to the gantry;
Comprising
The controller is
Move the marker member to the isocenter identification position,
From the respective positions of a plurality of traveling angles around the second axis of the gantry, the image is picked up by the imaging device,
The amount of adjustment of the gimbal mechanism required for aligning the irradiation axis of the X-rays emitted from the radiation generating device with the position of the marker member based on the position of the marker member picked up for each traveling angle Radiation therapy device that seeks. The radiotherapy apparatus according to claim 4,
The imaging apparatus is a radiotherapy apparatus that is the same as the detector. The radiotherapy apparatus according to claim 5,
The radiotherapy apparatus, wherein the marker member is a metal sphere. The radiotherapy apparatus according to claim 4,
The imaging apparatus is a radiotherapy apparatus that is a CCD camera attached to an X-ray emission end of the radiation generation apparatus. The radiotherapy apparatus according to claim 7,
The CCD camera includes a monochromatic light filter,
A radiotherapy apparatus that irradiates the marker member with monochromatic light having a wavelength capable of transmitting the monochromatic light when the isocenter is identified. A radiotherapy device according to claim 8, comprising:
The radiotherapy apparatus wherein the marker member is a nylon sphere. A radiotherapy apparatus according to claim 8 or 9, wherein
The marker member is supported on the outer surface by a marker support member The radiotherapy apparatus according to claim 10, comprising:
The marker member and the marker support member are radiotherapy apparatuses having different light reflectivities. A radiotherapy apparatus according to claim 11, comprising:
The marker member is a radiotherapy apparatus having a light reflectance higher than that of the marker support member. The radiotherapy apparatus according to any one of claims 7 to 12,
The said control apparatus is a radiotherapy apparatus which performs a binarization process with respect to the imaged image of the said marker member. The radiotherapy apparatus according to any one of claims 7 to 13,
The radiotherapy apparatus, wherein the marker member is larger than a detection limit of the CCD camera and smaller than a visual field range of the CCD camera. The radiotherapy apparatus according to claim 14, comprising:
The marker member is a radiotherapy apparatus having a size of 1/3 to 1/4 with respect to the visual field of the CCD camera. The radiotherapy apparatus according to any one of claims 4 to 15,
The said control apparatus is a radiotherapy apparatus which stores the adjustment amount of the said gimbal mechanism calculated | required for every said running angle in association with a turning angle and a running angle. A radiotherapy device according to claim 16, comprising:
In irradiating the irradiated object with X-rays,
The controller is
Based on the relationship between the stored adjustment amount of the gimbal mechanism and the turning angle and the traveling angle, the mounting angle of the radiation generator is adjusted by the gimbal mechanism at the traveling angle of the set turning angle,
A radiotherapy apparatus that irradiates the irradiated body with X-rays from the radiation generation apparatus after adjusting the mounting angle. The radiotherapy apparatus according to claim 16 or 17,
Furthermore,
A multi-leaf collimator that adjusts an irradiation field by cutting a part of the X-rays emitted from the radiation generator;
An alignment mechanism for adjusting the mounting position of the radiation generating device with respect to the gantry;
Comprising
The controller is
The rotational symmetry of the X-ray intensity distribution is evaluated by the detector for each traveling angle of each turning angle,
Based on the evaluation result of the rotational symmetry, obtain the adjustment amount of the alignment mechanism necessary to make the relative arrangement of the multi-leaf collimator and the radiation generator a desired relationship,
A radiotherapy apparatus that stores a correspondence relationship between the obtained adjustment amount of the alignment mechanism, a turning angle, and a traveling angle. A radiotherapy device according to claim 18, comprising:
In irradiating the irradiated object with X-rays,
The controller is
Based on the correspondence relationship between the stored adjustment amount of the alignment mechanism, the turning angle, and the traveling angle, the relative arrangement of the X-ray irradiation axis and the multi-leaf collimator becomes a desired relationship at the set angle. To adjust the mounting position of the radiation generator,
A radiotherapy apparatus that irradiates an irradiated body with X-rays from the radiation generation apparatus after adjusting the attachment position. A radiotherapy apparatus according to any of claims 16 to 19, wherein
The control device further includes:
Based on the adjustment amount of the gimbal mechanism determined for each traveling angle for each turning angle, adjust the mounting angle of the radiation generator for each traveling angle of each turning angle,
X-rays are emitted in a state where the mounting angle is adjusted, and an X-ray image of the marker member is captured by the detector,
Based on the magnitude of distortion of the X-ray image of the imaged marker member, the amount of angular displacement of the detector with respect to the gantry is obtained,
A radiotherapy apparatus for storing a correlation between an amount of angular displacement of the detector with respect to the gantry, a turning angle, and a traveling angle. A radiotherapy apparatus according to claim 20, comprising:
The control device further includes:
X-rays are emitted from the radiation generator at the set turning angle, and the X-ray image of the irradiated object is detected by the detector.
A radiotherapy apparatus that corrects a detected X-ray image of the irradiated object based on a correlation between a stored mounting angle displacement amount of the detector with respect to the gantry, a turning angle, and a traveling angle. The radiotherapy apparatus according to any one of claims 4 to 21,
The radiotherapy apparatus in which the traveling angle is set with respect to each position of a plurality of turning angles defined as an angle around the first axis of the gantry. The radiotherapy apparatus according to any one of claims 1 to 22,
Before the controller identifies the isocenter,
The radiation generator is disposed at a position where the gantry and the first axis intersect,
At each position of a plurality of turning angles, X-rays are emitted from the radiation generator, and the X-ray intensity distribution is detected by the detector,
A radiotherapy apparatus that adjusts the mounting angle of the radiation generating apparatus with respect to the gantry so that the X-ray irradiation axis coincides at any turning angle based on the detection result of the X-ray intensity distribution. The radiotherapy apparatus according to any one of claims 1 to 23,
Furthermore,
A horizontal axis adjusting light source that emits light in the horizontal direction from the isocenter height position,
Before the controller identifies the isocenter,
A radiotherapy apparatus that adjusts the position of the marker member in the height direction using a light beam emitted from the horizontal axis adjustment light source as an index. A gantry rotatable about a first axis passing through the isocenter and also rotatable around a second axis intersecting the first axis at the isocenter, and an image pickup disposed on the gantry A radiotherapy apparatus control method comprising:
Placing a marker member indicating an assumed isocenter position at a position generally assumed at the isocenter; and
From the plurality of positions of the swivel angle defined as the angle around the first axis of the gantry, the marker member arranged approximately at the isocenter position is imaged, and the visual field position in each of the captured images of the marker member Isocenter identification step for identifying the position of the isocenter based on
A method for controlling a radiotherapy apparatus comprising: A method for controlling a radiotherapy apparatus according to claim 25, comprising:
The method of controlling a radiotherapy apparatus, wherein the first axis is parallel to a vertical direction. A method for controlling a radiotherapy device according to claim 26, comprising:
In the isocenter identification step, when capturing an image of the marker member, the radiation generating apparatus controls the radiation therapy apparatus to capture an image of the marker member from a position where the first axis and the gantry intersect. . 28. The method of controlling a radiation therapy apparatus according to claim 25, wherein the radiation therapy apparatus further includes a radiation generator disposed in the gantry and the radiation generator via an isocenter. A detector for detecting the intensity distribution of X-rays emitted from the radiation generator, and a gimbal mechanism for adjusting the mounting angle of the radiation generator with respect to the gantry. , And
Furthermore,
Placing the marker member at the position identified in the isocenter identification step;
Capturing an image of the marker member from each of a plurality of travel angles defined as angles around the second axis of the gantry;
An adjustment amount of the mounting angle of the radiation generating apparatus with respect to the gantry necessary for aligning the X-ray irradiation axis with the position of the marker member based on the position of the marker member picked up for each traveling angle An adjustment amount determining step for obtaining
A method for controlling a radiotherapy apparatus comprising: A method for controlling a radiotherapy apparatus according to claim 28, comprising:
The imaging device is the detector;
In the step of capturing an image of the marker member from each position of the plurality of traveling angles, the marker member image emits X-rays from the radiation generator, and the intensity distribution of the X-rays is detected. A method of controlling a radiotherapy apparatus that is performed by detecting with an instrument. A method for controlling a radiotherapy apparatus according to claim 28, comprising:
The imaging apparatus is a radiotherapy apparatus that is a CCD camera attached to an X-ray emission end of the radiation generation apparatus so that a field center coincides with an irradiation axis of X-rays emitted from the radiation generation apparatus Control method. A method for controlling a radiation irradiation apparatus according to any one of claims 28 to 30,
Furthermore,
A method for controlling a radiotherapy apparatus, comprising: storing an adjustment amount of an attachment angle obtained for each traveling angle in association with a traveling angle. A method for controlling a radiotherapy apparatus according to claim 31,
Adjusting the mounting angle of the radiation generator at the set traveling angle based on the relationship between the stored adjustment amount of the mounting angle and the traveling angle;
Irradiating an irradiation target with X-rays from the radiation generator after adjusting the mounting angle;
A method for controlling a radiation apparatus comprising: A method for controlling a radiotherapy apparatus according to claim 31 or 32, comprising:
The radiotherapy apparatus further includes a multi-leaf collimator that cuts a part of the X-rays emitted from the radiation generation apparatus and adjusts the irradiation field,
Furthermore,
Evaluating the rotational symmetry of the X-ray intensity distribution emitted from the radiation generator for each of the travel angles;
A step of obtaining an adjustment amount of an attachment position of the radiation generating apparatus with respect to the gantry necessary for making a relative arrangement of the multi-leaf collimator and the X-ray irradiation axis a desired relationship based on a rotational symmetry evaluation result. When,
Storing a correspondence relationship between the adjustment amount of the mounting position and the traveling angle;
A method for controlling a radiotherapy apparatus comprising: A radiotherapy apparatus control method according to claim 33, comprising:
Based on the correspondence between the stored adjustment amount of the attachment position and the traveling angle, the attachment position of the radiation generator is set so that the X-ray irradiation axis and the multi-leaf collimator have a desired relation at the set angle. Adjusting steps,
After adjusting the mounting position, irradiating the irradiation target with X-rays from the radiation generating device;
A method for controlling a radiotherapy apparatus comprising: A method for controlling a radiotherapy apparatus according to any one of claims 31 to 34, comprising:
Furthermore,
Based on the adjustment amount obtained for each traveling angle, the mounting angle of the radiation generator is adjusted for each traveling angle, and X-rays are emitted with the mounting angle adjusted, and the marker member Capturing an X-ray image with the detector;
Obtaining an amount of angular displacement of the detector with respect to the gantry based on the magnitude of distortion of the imaged X-ray image of the marker member;
Storing the correlation between the amount of angular displacement of the detector attached to the gantry and the running angle of the detector;
A method for controlling a radiotherapy apparatus comprising: A method for controlling a radiotherapy apparatus according to claim 35, comprising:
Furthermore,
Capturing an X-ray image of the irradiated object at the set traveling angle;
Correcting the imaged X-ray image of the irradiated object based on a correlation between a stored angular displacement of the detector with respect to the gantry and a traveling angle;
A method for controlling a radiotherapy apparatus comprising: A control method for a radiotherapy apparatus according to any one of claims 28 to 36, comprising:
The method of controlling a radiotherapy apparatus, wherein the traveling angle is set with respect to each position of a plurality of turning angles defined as angles around the first axis of the gantry. A method for controlling a radiotherapy apparatus according to any one of claims 25 to 37, wherein
Furthermore,
Comprising a pre-alignment step performed prior to the isocenter identification step;
The pre-alignment step includes
Disposing the radiation generating device at a position where the gantry and the first axis intersect;
Detecting the intensity distribution of the X-rays emitted from the radiation generator from the respective positions of the plurality of turning angles;
Adjusting the mounting angle of the radiation generating device with respect to the gantry so that the X-ray irradiation axis coincides at any turning angle based on the detection result of the X-ray intensity distribution;
A method for controlling a radiation therapy apparatus. A method for controlling a radiotherapy apparatus according to any one of claims 25 to 38, comprising:
Furthermore,
Control of a radiotherapy apparatus including an isocenter height position setting step that is executed before the isocenter identification step and adjusts the position of the marker member in the height direction using a light beam emitted from the isocenter height position as an index Method.

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