CN116115912A - Method for determining position error of therapeutic beam of radiosurgery robot system - Google Patents

Method for determining position error of therapeutic beam of radiosurgery robot system Download PDF

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CN116115912A
CN116115912A CN202211619111.1A CN202211619111A CN116115912A CN 116115912 A CN116115912 A CN 116115912A CN 202211619111 A CN202211619111 A CN 202211619111A CN 116115912 A CN116115912 A CN 116115912A
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robot
determining
accelerator
isocenter
laser
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顾振宇
安陆军
菅影超
刘理想
李莉
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Jiangsu Ruier Medical Science & Technology Co ltd
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Jiangsu Ruier Medical Science & Technology Co ltd
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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N5/00—Radiation therapy
    • A61N5/10—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy
    • A61N5/1001—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy using radiation sources introduced into or applied onto the body; brachytherapy
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
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    • A61N5/10—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy
    • A61N5/103—Treatment planning systems
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N5/00—Radiation therapy
    • A61N5/10—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy
    • A61N5/1048—Monitoring, verifying, controlling systems and methods
    • A61N5/1049—Monitoring, verifying, controlling systems and methods for verifying the position of the patient with respect to the radiation beam
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N5/00—Radiation therapy
    • A61N5/10—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy
    • A61N5/1048—Monitoring, verifying, controlling systems and methods
    • A61N5/1075—Monitoring, verifying, controlling systems and methods for testing, calibrating, or quality assurance of the radiation treatment apparatus
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
    • B25J9/00—Programme-controlled manipulators
    • B25J9/10—Programme-controlled manipulators characterised by positioning means for manipulator elements
    • B25J9/12—Programme-controlled manipulators characterised by positioning means for manipulator elements electric
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    • G16H—HEALTHCARE INFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR THE HANDLING OR PROCESSING OF MEDICAL OR HEALTHCARE DATA
    • G16H20/00—ICT specially adapted for therapies or health-improving plans, e.g. for handling prescriptions, for steering therapy or for monitoring patient compliance
    • G16H20/40—ICT specially adapted for therapies or health-improving plans, e.g. for handling prescriptions, for steering therapy or for monitoring patient compliance relating to mechanical, radiation or invasive therapies, e.g. surgery, laser therapy, dialysis or acupuncture
    • A—HUMAN NECESSITIES
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    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N5/00—Radiation therapy
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    • A61N5/1048—Monitoring, verifying, controlling systems and methods
    • A61N5/1049—Monitoring, verifying, controlling systems and methods for verifying the position of the patient with respect to the radiation beam
    • A61N2005/105—Monitoring, verifying, controlling systems and methods for verifying the position of the patient with respect to the radiation beam using a laser alignment system
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N5/00—Radiation therapy
    • A61N5/10—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy
    • A61N5/1048—Monitoring, verifying, controlling systems and methods
    • A61N5/1049—Monitoring, verifying, controlling systems and methods for verifying the position of the patient with respect to the radiation beam
    • A61N2005/1061—Monitoring, verifying, controlling systems and methods for verifying the position of the patient with respect to the radiation beam using an x-ray imaging system having a separate imaging source
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N5/00—Radiation therapy
    • A61N5/10—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy
    • A61N2005/1092—Details
    • A61N2005/1097—Means for immobilizing the patient

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Abstract

The invention relates to a method for determining a treatment beam position error of a radiosurgery robot system, and relates to the technical field of radiosurgery robot system application. A radiosurgery robotic system comprising a robot carrying an accelerator, an image guided positioning system, and a flat panel detector, the method comprising: determining the installation error of the robot and the isocenter through an image guiding and positioning system and a flat panel detector; determining a machining error corresponding to the accelerator and an installation mechanical structure error; and determining the working space positioning errors corresponding to the robot and the accelerator configured by the robot. In the process of confirming the treatment beam errors of the radiosurgery robot system, conventional calibrating devices such as a calibrating tool, a virtual beam and a two-dimensional position sensitive detector are combined with the existing equipment in the system, so that the multi-dimensional errors which are all possessed by the multi-type radiosurgery robot system and can be quantified are obtained, the measuring cost is reduced, and meanwhile, the determining precision and the accuracy of the errors are improved.

Description

Method for determining position error of therapeutic beam of radiosurgery robot system
Technical Field
The invention relates to the technical field of radiosurgery robot system application, in particular to a method for determining a treatment beam position error of a radiosurgery robot system.
Background
The principle of radiotherapy is to irradiate the tumor with a certain dose by a radiation source, so as to eliminate tumor tissues. In recent years, radiation therapy techniques and equipment have changed greatly, and conventional radiation therapy has shifted to accurate radiosurgery. The accurate radiosurgery treatment refers to a new radiation treatment technology for carrying out accurate diagnosis, accurate positioning, accurate planning and accurate treatment on tumors. Regardless of the type of radiation therapy system, accurate therapy is that the position of the actual therapeutic beam relative to the isocenter (the accelerator source is the starting point, and a point in the tumor target is the target point) in the radiation therapy process is consistent with the position of the therapeutic beam relative to the isocenter in the therapy plan. The core criteria for planning treatment is to subject the tumor to sufficient radiation to eliminate it while ensuring that healthy tissue outside the tumor is exposed to as little radiation as possible. Radiosurgery robotic systems are one of the latest radiation treatment techniques and equipment compared to traditional conventional radiation treatment systems.
In the related art, the system hardware components of the radiosurgery robot system mainly include: a miniaturized linear accelerator, a six-degree-of-freedom robot carrying the accelerator, a six-degree-of-freedom robot treatment bed, an image guiding and positioning system and a respiratory motion tracking system are arranged; the software comprises the following components: treatment planning system software, data management system software, and treatment control system software. In treatment, the six-degree-of-freedom robot carries an accelerator, reaches a certain designated treatment node on the treatment sphere, performs treatment beam projection, and then, according to a treatment path planned by a treatment plan, the six-degree-of-freedom robot carries the accelerator to reach each treatment node, and completes beam projection one by one. In the related art, the calibration method for the beam position emitted by the radiosurgery robot system includes a method of CyberKnife treatment beam position calibration. It mainly includes two ways, in article The accuracy of dose localization for an image guided frameless radiosurgery system, chinese patent application No. 201880049677.0, calibration and verification of the position of a radiation-based treatment beam. Taking the chinese patent as an example, the general principle is to use a camera to acquire an image of a radiation beam incident on a body membrane, which is emitted by a radiation source. The method further includes determining a beam pointing offset based on the image; and calibrating the position of the radiation source based on the beam pointing offset.
However, in the related art, the test method in article The accuracy of dose localization for an image guided frameless radiosurgery system is long in time consumption and high in cost, needs to add system components, and has limitation in types of radiosurgery robot systems that can be tested due to the specificity of the test method. The method described in the chinese patent application 201880049677.0, calibration and verification of treatment beam position based on radiation, although improving most of the shortfalls in the article solution, the manufacturing cost of the body membrane is expensive, and the number of high precision cameras required in the process is high, so the total cost of the calibration method is extremely high, and the type of test is still limited, and the calibration of treatment beams with a treatment space of 4pi cannot be performed.
Disclosure of Invention
The invention aims to overcome the defects in the prior art, thereby providing a method for determining the position error of a therapeutic beam of a radiosurgery robot system, reducing the use cost of the system and improving the operation efficiency of the system.
The system comprises a robot, an image guided positioning system and a flat panel detector, wherein the robot carries an accelerator.
The method comprises the following steps:
the method comprises the steps that through a calibration tool and a mounting error calibration algorithm, the mounting error of a robot and an isocenter is determined through an image guiding and positioning system and a flat panel detector;
determining machining errors and mounting mechanical structure errors corresponding to the accelerator by means of the virtual beam, the two-dimensional position-sensitive detector and the beam dose instrument;
and determining the working space positioning errors corresponding to the robot and the accelerator configured by the robot under different working plans through the laser tracker.
In one possible implementation, the robot corresponds to a robot flange;
through the calibration frock, combine installation error calibration algorithm, confirm the installation error of robot and isocenter, include:
determining an imaging geometry center of the image guidance system in response to the robot and the image guidance positioning system being installed;
installing a calibration tool on a robot flange of the robot;
controlling the robot to reach at least three detection positions in an imaging geometric area of the image guidance system, and determining at least three groups of detection data corresponding to the at least three detection positions;
and determining the installation error of the robot and the isocenter based on at least three groups of detection data.
In one possible implementation, the calibration fixture includes a fixture mount, a connecting rod, and a metal ball;
the metal ball is connected with the tool fixing piece through a connecting rod.
In one possible implementation, the detection data includes a spatial transformation relationship of the isocenter coordinate system relative to the robot base, a spatial transformation relationship of the metal ball under the isocenter coordinate system, a spatial variation relationship of the robot flange at the robot base, and a spatial variation relationship of the metal ball relative to the robot flange;
determining an installation error of the robot with the isocenter based on at least three sets of detection data, comprising:
and determining the installation error of the robot and the isocenter by combining the homogeneous transformation matrix based on the spatial transformation relation of the isocenter coordinate system relative to the robot base, the spatial transformation relation of the metal ball under the isocenter coordinate system, the spatial transformation relation of the robot flange on the robot base and the spatial transformation relation of the metal ball relative to the robot flange.
In one possible implementation, determining the machining error and the mounting mechanical error corresponding to the accelerator by means of a virtual beam, by means of a two-dimensional position-sensitive detector and a beam dose instrument, comprises:
determining a virtual beam corresponding to the real beam according to the real beam data and the coaxiality deviation data;
configuring a two-dimensional position sensitive detector in the isocenter of the radiosurgery robot system;
controlling the robot to carry the accelerator to move at least three positions, and carrying out coordinate recording through the two-dimensional position sensitive detector under the condition of emitting the virtual beam to obtain at least three groups of coordinate data;
determining errors other than along the beam translation direction after accelerator manufacture and installation based on at least three sets of coordinate data;
determining output doses corresponding to different beam positions with the accelerator source vertically down;
errors in the direction of beam translation are determined and compensated for based on the output dose.
In an alternative embodiment, in the case of emitting a virtual beam, coordinate recording is performed by a two-dimensional position-sensitive detector, resulting in at least three sets of coordinate data, including:
the method comprises the steps of radiating the laser to a laser reflecting device, a laser transmitting device, a laser adjusting mechanism, a first film and a second film under an accelerator, wherein the first film and the second film are verification films of radiation equipment;
performing laser emission through a laser emission device, and performing beam adjustment by a laser adjustment device and a laser reflection device so that laser passes through the centers of the first film and the second film to determine a virtual beam;
determining a moving coordinate system in response to the virtual beam determination;
starting a laser emission device and a two-dimensional position-sensitive detector, driving a robot to move, and determining at least three positions of laser emitted by the laser emission device on a reference plane;
at least three sets of coordinate data are determined based on the at least three locations.
In an alternative embodiment, determining the output dose corresponding to the different beam positions with the accelerator source facing vertically downward includes:
setting an absolute output dose calibration point;
the ray source of the accelerator is vertically downward and irradiates to an absolute output dose calibration point;
based on the irradiation results, output doses corresponding to different beam positions are determined.
In an alternative embodiment, the robot corresponds to a robot flange;
determining, by the laser tracker, a working space positioning error corresponding to the robot under different work plans, comprising:
sticking at least three target seats of the laser tracker on the surface of the accelerator;
controlling the robot to move different positions in at least three treatment spaces, and recording position coordinates;
determining the position relation between the target seats of at least three laser trackers and the robot flange;
controlling the robot to move to a theoretical treatment beam position;
determining a position of the radiation source relative to the isocenter in response to the robot moving to the theoretical treatment beam position;
a workspace positioning error corresponding to the robot and the robot-configured accelerator is determined based on the position of the radiation source relative to the isocenter.
In an alternative embodiment, the radiosurgery robotic system is configured with a robotic application executed by a robot;
the method further comprises the steps of:
inputting an installation error of the robot and the isocenter, a machining error corresponding to the robot, an installation mechanical structure error corresponding to the robot and a space positioning error corresponding to the accelerator into a robot application program;
the robot application program controls the robot to carry out position adjustment so as to calibrate and remove errors.
The beneficial effects included in the technical scheme at least comprise:
in the process of carrying out treatment beam errors of the radiation shell robot system, conventional calibration devices such as a calibration tool, a virtual beam, a two-dimensional position sensitive detector and the like are combined with the existing equipment in the system, so that the multi-dimensional errors which are all possessed by the multi-type radiation surgical robot system and can be quantized are obtained, the measurement cost is reduced, and meanwhile, the determination precision and the accuracy of the errors are improved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 illustrates a schematic structural view of a radiosurgery robot system provided in an exemplary embodiment of the present application.
Fig. 2 is a flow chart illustrating a method for determining a treatment beam position error of a radiation crust robotic system according to an exemplary embodiment of the present application.
Fig. 3 illustrates a flow chart of another method for radiosurgery robotic system treatment beam position error determination provided by an exemplary embodiment of the present application.
Fig. 4 shows a schematic diagram of calibration of a robot and an isocenter installation error according to an exemplary embodiment of the present application.
Fig. 5 is a schematic diagram illustrating a determination of beam coaxiality error between a laser beam and an accelerator radiation source according to an exemplary embodiment of the present application.
Fig. 6 illustrates a schematic diagram of an accelerator absolute output dose error determination provided in an exemplary embodiment of the present application.
Fig. 7 shows a schematic diagram of a working space positioning error determination principle of a robot at different treatment plan beam positions according to an exemplary embodiment of the present application.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the embodiments of the present invention will be described in further detail with reference to the accompanying drawings.
Fig. 1 illustrates a schematic structural view of a radiosurgery robot system provided in an exemplary embodiment of the present application. Referring to fig. 1, the radiosurgery robotic system includes a robot 110, an image guided positioning system 120, and a flat panel detector 130. The robot 110 has a robot flange 111 and a robot base 112, the robot base 112 is used for carrying a robot body 113, and the robot flange 111 is located at an end of the robot body. Optionally, the end of the robot body is further correspondingly configured with an accelerator. The accelerator is not shown in fig. 1. In the present embodiment, the number of image guided positioning systems 120 corresponds to the number of flat panel detectors 130. As shown in fig. 1, the number of image guided positioning systems 120 and flat panel detectors 130 is 2.
It should be noted that in various embodiments of the present application, the radiosurgery robotic system should also include the necessary equipment to perform the treatment procedure, such as a robotic treatment couch, a respiratory motion tracking system, and the like. The present application is not limited to a complete implementation of a radiosurgical robotic system.
In this application, the software components corresponding to the radiosurgery robot system further include treatment planning system software, data management system software, and treatment control system software.
In connection with the radiosurgery robot system described in fig. 1, fig. 2 shows a schematic flow chart of a method for determining a position error of a treatment beam of the radiosurgery robot system according to an exemplary embodiment of the present application, and the method is described by taking application of the method to a computer device as an example, and the method includes:
step 201, determining the installation error of the robot and the isocenter through an image guiding and positioning system and a flat panel detector by means of a calibration tool and an installation error calibration algorithm.
In the embodiment of the application, in combination with the use process of the calibration fixture, under the combined acquisition of the image guiding and positioning system and the flat panel detector, the software equipment can determine the error existing under the condition that the robot is installed but not started to work.
Step 202, determining machining errors and mounting mechanical errors of the accelerator by means of a virtual beam, by means of a two-dimensional position-sensitive detector and a beam dose instrument.
In the process of installing the accelerator, there are mechanical structure errors left during installation and machining errors which are different from standard dimensions in the machining process, and in the embodiment of the application, experiments are carried out through the virtual beam and by means of the two-dimensional position-sensitive detector so as to determine the machining errors and the mechanical structure errors during installation.
Step 203, determining the working space positioning errors corresponding to the robot and the accelerator configured by the robot under different working plans by a laser tracker.
In the embodiment of the application, the robot and the accelerator have inaccurate conditions in the space positioning process, so that the working space positioning error is determined through the position difference of the laser tracker in space positioning under different working modes.
It should be noted that, in the embodiments of the present application, the error calibration process is completed by the computer device after the error value is input after the error determination is completed.
In summary, in the process of performing treatment beam errors of the radiation shell robot system, the method provided by the embodiment of the application combines the conventional calibration devices such as the calibration tool, the virtual beam, the two-dimensional position sensitive detector and the like in the system to obtain the multi-dimensional errors which are all of the multi-type radiation surgical robot system and can be quantized, so that the measurement cost is reduced, and meanwhile, the determination precision and the accuracy of the errors are improved.
Next, a specific execution flow in the different processes will be described. Fig. 3 is a flow chart illustrating another method for determining a position error of a treatment beam of a radiosurgery robot system according to an exemplary embodiment of the present application, and the method is applied to the radiosurgery robot system shown in fig. 1, and includes:
in response to the robot and the image guidance positioning system being installed, an imaging geometry center of the image guidance system is determined, step 301.
Steps 301 to 304 are specific flows of the installation errors of the robot and the isocenter provided in the embodiments of the present application. In this embodiment, please refer to fig. 4, the working principle of the image guidance system is to control 2 Kv-level X-ray tubes to emit rays to irradiate on 2 flat panel detectors 410, then collect images on the flat panel detectors 410, and calculate the three-dimensional spatial position of the object in the imaging region with the imaging geometric center as an origin 420, that is, under an isocenter coordinate system according to the 2-3-dimensional image registration principle. After the robot 430 is installed, the origin 420 becomes the isocenter and is realized as a fixed position, in this application, the tool by which the calibration is performed is the calibration fixture 440.
Step 302, installing a calibration fixture on a robot flange of a robot.
In this application embodiment, the calibration frock includes frock mounting, connecting rod and metal ball. The metal ball is connected with the tool fixing piece through a connecting rod. Alternatively, the length of the connecting rod is 400mm-1000mm. The purpose of the connecting rod length of more than 400mm is to avoid the condition that the connecting rod length is too short, and the robot flange possibly enters an imaging area of the image guiding system, so that the normal working condition of the image guiding system is disturbed. The purpose of less than 1000mm is to avoid the situation that the calibration rod itself is mechanically deformed when the calibration rod is too long, thereby increasing the calibration error. The radius of the metal pellet is 0.5-1mm.
Step 303, controlling the robot to reach at least three detection positions within the imaging geometry of the image guidance system and determining at least three sets of detection data corresponding to the at least three detection positions.
In the process, the metal ball carrying the tool by the robot is controlled to reach more than 3 arbitrary different positions in an imaging geometric area of a 200-image guiding system, and then the spatial position of the ball in an isocenter coordinate system, the spatial position and the rotation angle of a robot flange in a robot base, which are given by the robot control cabinet, are respectively recorded by the image guiding system. It should be noted that, the robot control cabinet and the parameter obtaining mode in the process are all conventional technologies, and the equipment with robot control software and hardware can be controlled.
Step 304, determining the installation error of the robot and the isocenter by combining the homogeneous transformation matrix based on the spatial transformation relation of the isocenter coordinate system relative to the robot base, the spatial transformation relation of the metal ball under the isocenter coordinate system, the spatial transformation relation of the robot flange on the robot base and the spatial transformation relation of the metal ball relative to the robot flange.
In the embodiment of the present application, assuming that the spatial transformation relationship of the isocenter coordinate system with respect to the robot base is T1, the spatial transformation relationship of the metal pellet with respect to the isocenter coordinate system is T2, the spatial transformation relationship of the robot flange with respect to the robot base is T3, and the spatial transformation relationship of the metal pellet with respect to the robot flange is T4, the following formula 1 is used:
T1×T2＝T3×T4
wherein it is assumed that
Figure BDA0003998438510000061
Homogeneous transformation matrix of 4×4, order for easy expression
Figure BDA0003998438510000062
Where Ti is the i-th data acquisition point, and not the definitions of T1, T2, T3, and T4 described above. Ti (Ti) Rot Representing a rotation portion of the robot flange with respect to the robot base in the ith robot data acquisition point, in the latter case, the Trans subscript represents a translation of the robot flange with respect to the robot base, and the Rot subscript represents a rotation of the robot flange with respect to the robot base
Equation 2 is derived from equation 1 as follows:
T3 Trans +T3 Rot ×T4 Trans _T1 Rot ×T2 Trans ＝T1 Trans
assuming that i number of position data of the metal ball under the isocenter coordinate system and position data of the corresponding robot flange on the robot base are provided, wherein i is more than or equal to 3, and the following formulas 3 to 5 are combined:
A i ＝T3 Trans(i+1) -T3 Trans(i) +(T3 Rot(i+1) -T3 Rot(i) )×T4 Trans
B i ＝T2 Trans(i+1) -T2 Trans(i)
Figure BDA0003998438510000071
finding out T4 when F is the minimum value according to the principle of least square method Trans Then T4 at this time Trans Substituting formula 2, calculating the installation error T1 of the robot and the isocenter by using the primordial elimination method and a plurality of groups of position data Trans And T1 Rot 。
In step 305, a virtual beam corresponding to the real beam is determined based on the real beam data and the coaxiality deviation data.
Steps 305 to 314 are processes of determining a machining error corresponding to the accelerator and an installation mechanical structure error. In the embodiment of the application, other errors without translation of the beam direction are determined first, and then the errors with translation of the beam direction are determined through a beam dosage instrument.
In the embodiment of the application, the virtual beam is generated by a corresponding laser generating instrument and has coaxiality within 0.5mm with the real beam emitted by the robot.
At step 306, a two-dimensional position sensitive detector is configured at an isocenter of the radiosurgery robotic system.
The two-dimensional position sensitive detector has the function of collecting data on a two-dimensional coordinate system. Optionally, the position sensitive detector is disposed near the isocenter.
And step 307, radiating the laser light to the laser reflection device, the laser emission device, the laser adjusting mechanism, the first film and the second film under the accelerator.
Referring to fig. 5, in the embodiment of the present application, the accelerator radiation source 511 corresponding to the accelerator 510 is coaxial with the first film 520 and the second film 530, and the first film 520 and the second film 530 are radiation equipment verification films, that is, have the functions of receiving laser light and generating corresponding verification characterization. The laser emitting device 540 and the laser reflecting device 550 are located below the accelerator 510. And the laser emitting device 540 corresponds to a laser adjustment mechanism 560 having a translational and rotational adjustment function for the laser emitting device 540.
In step 308, the laser is emitted by the laser emitting device, and the laser beam is adjusted by the laser adjusting device and the laser reflecting device, so that the laser passes through the centers of the first film and the second film to determine the virtual beam.
This process is a virtual beam adjustment process, please refer to fig. 5, in which the distance between the accelerator source 511 and the first film is H1, the distance between the accelerator source 511 and the second film is H2, wherein H1 is between 600mm and 1200mm, and H2 is between 1600mm and 2000mm, and the laser adjustment mechanism 560 is used to make the device emitted by the laser emitting device 540 irradiate the center of the first film 520 and the second film 530 with the strongest color change degree, and control the center error.
In response to the virtual beam determination, a moving coordinate system is determined 309.
The process is the process of determining the coordinate system. The two-dimensional position sensitive detector will determine one dimension as the X-direction of robot movement and the other dimension as the Y-direction of robot movement to establish a coordinate system.
And 310, starting a laser emitting device and a two-dimensional position sensitive detector, and driving a robot to move to determine at least three positions of laser emitted by the laser emitting device on a reference plane.
The process is the process of selecting three positions of the robot. In this process, the accelerator is located at a distance of 600-1600mm above the position sensor.
At least three sets of coordinate data are determined based on the at least three locations 311.
In this embodiment of the present application, the data displayed by the parameter display function corresponding to the robot is [ X0, y 0, z h ], and the three directions of the robot coordinate system are parallel to the three directions selected above, that is, the rotation angle is [0, 0], in which case, the collection of at least three sets of coordinate data is completed.
After determining the three sets of coordinate data, the following equations 6 to 8 are determined:
Figure BDA0003998438510000081
Figure BDA0003998438510000082
H＝h+ΔX
wherein, pix and Piy are measured by a two-dimensional position sensitive detector, and h is the height difference of the theoretical tool coordinate system under the user coordinate system displayed by the robot system. Wherein:
Δx, Δy, Δz are the errors of the values of the actual tool coordinate system relative to flange translation and the theoretical tool coordinate system relative to flange translation, respectively.
Δa, Δb, Δc are angles of rotation of the actual tool coordinate system relative to the theoretical tool coordinate system, respectively, and when there is no error between the actual tool coordinate system and the theoretical tool coordinate system, the three rotation angles are all 0 °.
According to more than 3 different h values and corresponding Pix and Piy, the practical tool coordinate system, that is, all practical values of the translational error of the beam direction of the accelerator ray source beam relative to the flange coordinate system can be calculated by combining the formulas 6, 7 and 8 with the least square method.
At step 312, an absolute output dose calibration point is set.
At step 313, the accelerator source is directed vertically downward and irradiated to an absolute output dose calibration point.
In the present example, the setting of the absolute output dose calibration point was done 15mm below water and irradiation was done vertically down outside 800mm using an accelerator. In the embodiment of the application, the principle of the error determination process is schematically shown in fig. 6.
Based on the irradiation results, output doses corresponding to different beam positions are determined, step 314.
The process is the dosage value determining process. Alternatively, the error of the output dose from the preset dose may be indicative of the error of the beam direction translation.
At step 315, at least three targets of the laser tracker are adhered to the surface of the accelerator.
Steps 315 to 320 are processes of performing working space positioning errors corresponding to the robot and the accelerator configured by the robot under different working plans. In the embodiment of the application, the setting of the laser tracker is performed first. Optionally, the positions of the 3 target seats are required to be not in the same straight line, and the laser tracker can be ensured to collect the positions of at least 1 target seat when the beam position is ensured to be at any position in the 4 pi global working space.
Step 316, controlling the robot to move different positions in at least three treatment spaces and recording the position coordinates.
In step 317, the positional relationship between the target holder of the at least three laser trackers and the robot flange is determined.
Please refer to fig. 7. The laser tracker 710 is opposite the robot 720, and the robot flange 721 is located at the end of the robot 720. The process is a process of the position relation between the target seat and the robot flange after the target seat is arranged.
At step 318, the robot is controlled to move to the theoretical treatment beam position.
In response to the robot moving to the theoretical treatment beam position, a position of the radiation source relative to the isocenter is determined 319.
In the present embodiment, the different positions described in step 316 have an inclusive relationship to the theoretical treatment beam position described in step 318.
Step 320, determining a workspace positioning error corresponding to the robot and the accelerator configured by the robot based on the position of the radiation source relative to the isocenter.
In the embodiment of the present application, the positional transformation relationship of the virtual robot tool coordinate system (target holder) with respect to the robot flange is T11.
The positional conversion relation of the virtual robot tool coordinate system with respect to the isocenter is T12.
The positional transformation relation of the actual robot tool coordinate system (accelerator ray source) with respect to the robot flange is T13, which can be determined in step 311.
The positional transformation relation of the actual robot tool coordinate system with respect to the isocenter is T1.
Then there is the following equation 9:
T14 i ＝T12 i ×T11 -1 ×T13
wherein, it is assumed that
Figure BDA0003998438510000091
Homogeneous transformation matrix of 4×4, order for easy expression
Figure BDA0003998438510000092
At each beam position, the error of the accelerator source translation relative to the isocenter is calculated, and then beam position error compensation is accomplished by the translation robot. After the target seat position is acquired at a certain beam position, at this time:
T14 Rot ＝T12 Rot ，T11 Rot ＝T12 Rot
t11Trans is equal to the translation of the backing plate relative to the robot flange that can capture the position of the backing plate.
Substituting all variables into equation 9, T14 can be calculated Trans The value is the position of the source under the isocenter. By comparison with T14 Trans The theoretical value of the radiation source in the isocenter coordinate system under the treatment plan beam position can be directly used as a robot moving instruction to enable the robot to move to the theoretical beam position.
Step 321, the installation error of the robot and the isocenter, the machining error corresponding to the accelerator, the installation mechanical structure error corresponding to the accelerator and the spatial positioning error corresponding to the accelerator are input into the robot application program.
In step 322, the robot application program controls the robot to perform position adjustment so as to calibrate and remove errors.
As previously indicated, the radiosurgery robotic system is configured with a robotic application executed by the robot. In this case, the error is inputted, so that the error can be calibrated and cleared.
In summary, in the process of performing treatment beam errors of the radiosurgery robot system, the method provided by the embodiment of the application combines the conventional calibration devices such as the calibration tool, the virtual beam, the two-dimensional position-sensitive detector and the like in the system to obtain the multi-dimensional errors which are all of the multi-type radiosurgery robot system and can be quantized, so that the measurement cost is reduced, and meanwhile, the determination precision and the accuracy of the errors are improved.
The foregoing description of the preferred embodiments of the present invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, alternatives, and improvements within the spirit and principles of the present invention.

Claims (9)

1. A method for determining the position error of a therapeutic beam of a radiosurgery robot system, which is characterized in that the method is applied to the radiosurgery robot system, the radiosurgery robot system comprises a robot, an image guiding and positioning system and a flat panel detector, and the robot carries an accelerator;
the method comprises the following steps:
determining the installation error of the robot and the isocenter through the image guiding and positioning system and the flat panel detector by means of a calibration tool and an installation error calibration algorithm;
determining machining errors and mounting mechanical structure errors corresponding to the accelerator by means of a virtual beam, by means of a two-dimensional position-sensitive detector and a beam dose instrument;
and determining working space positioning errors corresponding to the robot and the accelerator configured by the robot under different working plans through a laser tracker.
2. The method of claim 1, wherein the robot corresponds to a robotic flange;
through the calibration frock, combine installation error calibration algorithm, confirm the installation error of robot and isocenter, include:
determining an imaging geometry center of the image-guided system in response to the robot and the image-guided positioning system being installed;
installing the calibration fixture on a robot flange of the robot;
controlling the robot to reach at least three detection positions in an imaging geometric area of the image guidance system, and determining at least three groups of detection data corresponding to the at least three detection positions;
and determining the installation error of the robot and the isocenter based on at least three groups of detection data.
3. The method of claim 2, wherein the calibration fixture comprises a fixture, a connecting rod, and a metal ball;
the metal ball is connected with the tool fixing piece through the connecting rod.
4. A method according to claim 3, wherein the detection data comprises a spatial transformation relationship of an isocenter coordinate system with respect to the robot base, a spatial transformation relationship of the metal ball under the isocenter coordinate system, a spatial variation relationship of the robot flange with respect to the robot base, and a spatial variation relationship of the metal ball with respect to the robot flange;
the determining the installation error of the robot and the isocenter based on at least three sets of detection data includes:
and determining the installation error of the robot and the isocenter by combining the homogeneous transformation matrix based on the spatial transformation relation of the isocenter coordinate system relative to the robot base, the spatial transformation relation of the metal ball under the isocenter coordinate system, the spatial transformation relation of the robot flange on the robot base and the spatial transformation relation of the metal ball relative to the robot flange.
5. The method according to claim 1, wherein said determining machining errors and mounting mechanical structure errors corresponding to said accelerator by means of a virtual beam, by means of a two-dimensional position sensitive detector and a beam dose instrument, comprises:
determining a virtual beam corresponding to the real beam according to the real beam data and the coaxiality deviation data;
configuring the two-dimensional position sensitive detector at an isocenter of the radiosurgery robotic system;
controlling the robot to carry the accelerator to move at least three positions, and carrying out coordinate recording through the two-dimensional position sensitive detector under the condition of emitting a virtual beam to obtain at least three groups of coordinate data;
determining errors other than along a beam translation direction after the accelerator is manufactured and installed based on the at least three sets of coordinate data;
determining output doses corresponding to different beam positions with the radiation source of the accelerator vertically down;
an error in the direction of beam translation is determined and compensated for based on the output dose.
6. The method according to claim 5, wherein the coordinate recording by the two-dimensional position-sensitive detector in the case of emitting a virtual beam, results in at least three sets of coordinate data, comprising:
the method comprises the steps that the laser is emitted to a laser reflecting device, a laser emitting device, a laser adjusting mechanism, a first film and a second film under the accelerator, wherein the first film and the second film are verification films of radiation equipment;
performing laser emission through the laser emission device, and performing beam adjustment by means of the laser adjustment device and the laser reflection device so that laser passes through the centers of the first film and the second film to determine the virtual beam;
determining a moving coordinate system in response to the virtual beam determination;
starting the laser emission device and the two-dimensional position-sensitive detector, driving the robot to move, and determining at least three positions of laser emitted by the laser emission device on a reference plane;
at least three sets of the coordinate data are determined based on the at least three locations.
7. The method of claim 5, wherein determining output doses corresponding to different beam positions with the accelerator source vertically down comprises:
setting an absolute output dose calibration point;
directing the accelerator source vertically downward and irradiating the absolute output dose calibration point;
based on the irradiation results, output doses corresponding to different beam positions are determined.
8. The method of claim 1, wherein the robot corresponds to a robotic flange;
the method for determining the working space positioning error corresponding to the robot under different working plans by the laser tracker comprises the following steps:
pasting at least three target seats of the laser tracker on the surface of the accelerator;
controlling the robot to move different positions in at least three treatment spaces, and recording position coordinates;
determining the position relation between the target seats of the at least three laser trackers and the robot flange;
controlling the robot to move to a theoretical treatment beam position;
determining a position of a radiation source relative to an isocenter in response to the robot moving to the theoretical treatment beam position;
a workspace positioning error corresponding to the robot and the accelerator configured by the robot is determined based on the position of the radiation source relative to an isocenter.
9. The method of claim 1, wherein the radiosurgical robotic system is configured with a robotic application executed by a robot;
the method further comprises the steps of:
inputting an installation error of the robot and the isocenter, a machining error corresponding to the accelerator, an installation mechanical structure error corresponding to the accelerator, and a spatial positioning error corresponding to the accelerator into the robot application;
and controlling the robot to carry out position adjustment through the robot application program so as to calibrate and remove errors.
CN202211619111.1A 2022-12-14 2022-12-14 Method for determining position error of therapeutic beam of radiosurgery robot system Pending CN116115912A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117697828A (en) * 2024-02-05 2024-03-15 苏州铸正机器人有限公司 Surgical robot precision measurement tool and precision measurement method

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117697828A (en) * 2024-02-05 2024-03-15 苏州铸正机器人有限公司 Surgical robot precision measurement tool and precision measurement method
CN117697828B (en) * 2024-02-05 2024-04-26 苏州铸正机器人有限公司 Surgical robot precision measurement tool and precision measurement method

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