Positioning system for radiotherapy

Abstract

The present invention discloses a positioning system for radiotherapy. The system includes: a bed board, on which a measurement tooling is installed, and a marking ball is installed on the measurement tooling; a robotic arm, which is connected to the bed board and is used to adjust the position of the bed board; an optical tracker, which is used to measure the position coordinates of the marking ball in real time; a positioning control device, which is respectively connected to the robotic arm and the optical tracker, and is used to obtain the position deviation and attitude angle deviation of the robotic arm according to the position coordinates of the marking ball, and to correct the positioning of the bed board by the robotic arm according to the position deviation and attitude angle deviation. Thus, this system improves the accuracy of proton and heavy ion radiotherapy positioning without affecting the treatment rate and treatment effect.

Description

Technical Field

[0001] The present invention relates to the technical field of proton heavy ion therapy, and in particular, to a positioning system for radiotherapy. Background Art

[0002] Radiotherapy is one of the main means for treating malignant tumors. Proton heavy ion therapy is a type of radiotherapy, which mainly uses an accelerator to generate proton or heavy ion beams with a certain energy. The beam is transmitted to the target area through a beam transmission system, and the depth and shape of the beam are adjusted to perform a high-energy "targeted sniper" on the tumor. The proton beam or heavy ion beam can be adjusted according to the depth of the location of the tumor to suppress the release of energy near the skin and before reaching the tumor. Once it reaches the tumor, it will instantaneously release a large dose of energy, and immediately stop releasing energy after passing through the tumor, forming an energy release trajectory called the "Bragg peak".

[0003] The positioning system for radiotherapy is one of the core components in new radiotherapy systems such as proton heavy ion therapy. It is a necessary carrier for proton heavy ion therapy, mainly to accurately position the patient to the required position and posture for treatment, so as to achieve accurate treatment and "directed blasting". Clinical practice shows that the accuracy of proton heavy ion therapy positioning will directly affect the treatment effect. However, since most of the currently commonly used radiotherapy patient positioning systems use multi-joint movements for positioning, whether the patient lies on (a large load) and different treatment postures will cause different degrees of position deviation, deformation, and mechanical position deviation of the positioning system for radiotherapy itself. Summary of the Invention

[0004] The present invention aims to at least partly solve one of the technical problems in the related art. To this end, an object of the present invention is to provide a positioning system for radiotherapy, which can improve the accuracy of proton heavy ion therapy positioning without affecting the treatment rate and treatment effect.

[0005] To achieve the above object, an embodiment of the first aspect of the present invention provides a positioning system for radiotherapy. The system includes: a bed board, on which a measuring tooling is installed, and a marking ball is installed on the measuring tooling; a robotic arm, which is connected to the bed board and is used to adjust the position of the bed board; an optical tracker, which is used to measure the position coordinates of the marking ball in real time; a positioning control device, which is respectively connected to the robotic arm and the optical tracker, and is used to obtain the position deviation and attitude angle deviation of the robotic arm according to the position coordinates of the marking ball, and correct the positioning of the bed board by the robotic arm according to the position deviation and the attitude angle deviation.

[0006] According to an embodiment of the present invention, a laser tracker target ball is further installed on the measurement tooling, and the positioning control device is further configured to: when the robotic arm is at the origin position in different treatment postures, obtain the position coordinates of the laser tracker target ball through the laser tracker, and based on the position coordinates of the laser tracker target ball and the relative position between the laser tracker target ball and the marker ball, obtain the theoretical position coordinates of the marker ball, and calibrate the error of the optical tracker according to the theoretical position coordinates of the marker ball and the position coordinates of the marker ball measured by the optical tracker; wherein, before obtaining the position deviation and attitude angle deviation of each joint of the robotic arm according to the position coordinates of the marker ball, the positioning control device is further configured to correct the position coordinates of the marker ball according to the calibration error of the optical tracker.

[0007] According to an embodiment of the present invention, when obtaining the position deviation and attitude angle deviation of the robotic arm according to the position coordinates of the marker ball, the positioning control device is specifically configured to: obtain the mapping relationship among the world coordinate system, the robotic arm coordinate system, and the optical tracker coordinate system, obtain the actual position and actual attitude angle of the robotic arm according to the mapping relationship and the position coordinates of the marker ball, and obtain the position deviation according to the actual position and the theoretical position of the robotic arm, and obtain the attitude angle deviation according to the actual attitude angle and the theoretical attitude angle of the robotic arm, wherein the mapping relationship is established according to the position relationship among the marker ball, the robotic arm, and the optical tracker.

[0008] Further, the mapping relationship is represented by the following formula:

[0009]

[0010] wherein, W3 is the optical tracker coordinate system, W2 is the robotic arm coordinate system, and W1 is the world coordinate system, and are respectively the rotation matrix of W3 relative to W2 and the transformation matrix of W2 relative to W1.

[0011] According to an embodiment of the present invention, when correcting the positioning of the bed board by the robotic arm according to the position deviation and the attitude angle deviation, the positioning control device is specifically configured to: when the position deviation exceeds a first set threshold and the attitude angle deviation exceeds a second set threshold, obtain the motion deviation of each joint of the robotic arm according to the position deviation and the attitude angle deviation through an inverse solution algorithm, and adjust the motion of the corresponding joint according to the motion deviation to correct the positioning of the bed board.

[0012] Further, when the positioning control device corrects the positioning of the bed board through the robotic arm according to the position deviation and the attitude angle deviation, it is specifically configured to: divide the movement trajectory of the robotic arm into N segments, and at i*T S time, predict the position deviation and the attitude angle deviation corresponding to the (i + 1)-th segment of the movement trajectory according to the position deviation and the attitude angle deviation corresponding to the i-th segment of the movement trajectory, and correct the movement of the robotic arm in the (i + 1)-th segment according to the predicted position deviation and the attitude angle deviation corresponding to the (i + 1)-th segment of the movement trajectory, where N = T / T S , T is the correction period, and T S is the period of measurement and data feedback of the optical tracker.

[0013] According to an embodiment of the present invention, the positioning control device is further configured to: obtain the running speed of the robotic arm according to the position coordinates of the marker ball measured in real time, and when the running speed is less than the theoretical speed and the difference exceeds a third set threshold, control the robotic arm to stop immediately.

[0014] According to an embodiment of the present invention, the positioning control device is further configured to: store the theoretical data and the measurement data of the robotic arm in different treatment postures to obtain a database file, and upgrade the control parameters of the robotic arm according to the database file.

[0015] According to an embodiment of the present invention, the measurement tooling includes a first component and a second component. The first component is used to install the laser tracker target ball, and the second component is used to install the marker ball. The first component and the second component are independently arranged and detachable, and the laser tracker target ball and the marker ball are detachably installed.

[0016] According to an embodiment of the present invention, the positioning control device is in wired communication connection with the optical tracker.

[0017] The positioning system for radiotherapy according to the embodiment of the present invention improves the positioning accuracy of proton and heavy ion radiotherapy on the basis of not affecting the treatment rate and the treatment effect.

[0018] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be understood through the practice of the present invention. Description of the Drawings

[0019] Figure 1 is a schematic structural diagram of a positioning system for radiotherapy according to an embodiment of the present invention;

[0020] Figure 2 is a schematic structural diagram of a positioning system for radiotherapy according to a specific embodiment of the present invention;

[0021] Figure 3 It is a schematic structural diagram of a measurement tooling of an embodiment of the present invention. Detailed implementation manners

[0022] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are intended to explain the present invention and should not be construed as a limitation to the present invention.

[0023] Below will be combined with the specification appendix Figures 1-3 And specific implementation manners to describe in detail the positioning system for radiotherapy of the embodiments of the present invention.

[0024] Figure 1 It is a schematic structural diagram of a positioning system for radiotherapy of an embodiment of the present invention. As Figure 1 shown, the positioning system 100 for radiotherapy includes: a bed board 10, a robotic arm 20, an optical tracker 30, and a positioning control device 40. Among them, referring to Figures 2-3 , a measurement tooling 11 is installed on the bed board 10, and a marker ball 1 is installed on the measurement tooling 11; the robotic arm 20 is connected to the bed board 10 and is used to adjust the position of the bed board 10; the optical tracker 30 is used to measure the position coordinates of the marker ball 1 in real time.

[0025] In this embodiment, the positioning control device 40 is respectively connected to the robotic arm 20 and the optical tracker 30, and is used to obtain the position deviation and attitude angle deviation of the robotic arm 20 according to the position coordinates of the marker ball 1, and to correct the positioning of the bed board 10 through the robotic arm 20 according to the position deviation and attitude angle deviation.

[0026] Specifically, the position of the robotic arm 20 can be obtained by a laser tracker. However, since the laser tracker can only obtain the position of the robotic arm 20 when the robotic arm 20 stops, therefore, the laser tracker cannot achieve the purpose of real-time tracking of the robotic arm 20. In the present invention, the positioning control device 40 measures the position coordinates of the marker ball 1 in real time through the optical tracker 30, and then obtains the position of the robotic arm 20 according to the position coordinates of the marker ball 1, so as to achieve the purpose of real-time tracking of the robotic arm 20. Furthermore, the positioning control device 40 obtains the position deviation and attitude angle deviation of the robotic arm 20 according to the position coordinates of the marker ball 1, and corrects the positioning of the bed board 10 through the robotic arm 20 according to the position deviation and attitude angle deviation.

[0027] It should be noted that the positioning control device 40 is in wired communication connection with the optical tracker 30. Specifically, the optical tracker 30 and the positioning control device 40 establish a communication connection through a network cable, enabling the data of the optical tracker 30 to be quickly transmitted to the positioning control device 40.

[0028] Thus, the positioning system for radiotherapy can ensure the accuracy of treatment positioning and treatment, and reduce the influence of position deviation, deformation caused by the patient's weight, and mechanical position deviation of the positioning system itself on the accuracy.

[0029] As an example, as Figure 3 shown, a laser tracker target ball 2 is also installed on the measuring tooling 11. The positioning control device 40 is further configured to: when the robotic arm 20 is at the origin position in different treatment postures, obtain the position coordinates of the laser tracker target ball 2 through the laser tracker, and based on the position coordinates of the laser tracker target ball 2 and the relative position between the laser tracker target ball 2 and the marker ball 1, obtain the theoretical position coordinates of the marker ball 1, and calibrate the error of the optical tracker 30 based on the theoretical position coordinates of the marker ball 1 and the position coordinates of the marker ball 1 measured by the optical tracker 30.

[0030] Among them, the measuring tooling 11 may include a first component 111 and a second component 112. The first component 111 is used to install the laser tracker target ball, and the second component 112 is used to install the marker ball 1. The first component 111 and the second component 112 are independently provided and detachable, and the laser tracker target ball 2 and the marker ball 1 are detachably installed.

[0031] It should be noted that before the positioning control device 40 obtains the position deviation and attitude angle deviation of each joint of the robotic arm 20 based on the position coordinates of the marker ball 1, it is further configured to correct the position coordinates of the marker ball 1 according to the calibration error of the optical tracker 30.

[0032] Furthermore, when the positioning control device 40 obtains the position deviation and attitude angle deviation of the robotic arm 20 based on the position coordinates of the marker ball 1, it is specifically configured to: obtain the mapping relationship among the world coordinate system, the robotic arm coordinate system, and the optical tracker coordinate system, obtain the actual position and actual attitude angle of the robotic arm 20 according to the mapping relationship and the position coordinates of the marker ball 1, and obtain the position deviation according to the actual position and the theoretical position of the robotic arm 20, and obtain the attitude angle deviation according to the actual attitude angle and the theoretical attitude angle of the robotic arm 20, where the mapping relationship is established based on the position relationship among the marker ball 1, the robotic arm 20, and the optical tracker 30.

[0033] Specifically, the mapping relationship is represented by the formula where W3 is the optical tracker coordinate system, W2 is the robotic arm coordinate system, and W1 is the world coordinate system. and They are respectively the rotation matrix of W3 relative to W2 and the transformation matrix of W2 relative to W1. Then, based on the mapping relationship and the position coordinates of the marker ball 1, the actual position (X0, Y0, Z0) and the actual attitude angles (RX0, RY0, RZ0) of the robotic arm 20 are obtained. Then, based on the actual position (X0, Y0, Z0) of the robotic arm 20 and the theoretical position (X0′, Y0′, Z0′) of the robotic arm 20, the position deviation (ΔX0, ΔY0, ΔZ0) is obtained. Based on the actual attitude angles (RX0, RY0, RZ0) of the robotic arm 20 and the theoretical attitude angles (RX0′, RY0′, RZ0′) of the robotic arm 20, the attitude angle deviation (ΔRX0, ΔRY0, ΔRZ0) is obtained, where ΔX0 = X0 - X0′, ΔY0 = Y0 - Y0′, ΔZ0 = Z0 - Z0′; ΔRX0 = RX0 - RX0′, ΔRY0 = RY0 - RY0′, ΔRZ0 = RZ0 - RZ0′.

[0034] Thus, the positioning control device 40 obtains the position deviation based on the actual position and the theoretical position of the robotic arm 20, and obtains the attitude angle deviation based on the actual attitude angle and the theoretical attitude angle of the robotic arm 20.

[0035] Furthermore, when the positioning control device 40 corrects the positioning of the bedplate 10 through the robotic arm 20 according to the position deviation and the attitude angle deviation, it is specifically used for: when the position deviation exceeds the first set threshold and the attitude angle deviation exceeds the second set threshold, obtaining the motion deviation of each joint of the robotic arm 20 according to the position deviation and the attitude angle deviation through the inverse kinematics algorithm, and adjusting the motion of the corresponding joint according to the motion deviation to correct the positioning of the bedplate 10.

[0036] Specifically, when the position deviation exceeds the first set threshold and the attitude angle deviation exceeds the second set threshold, the positioning control device 40 obtains the motion deviation of each joint of the robotic arm 20 according to the position deviation and the attitude angle deviation through the inverse kinematics algorithm. Furthermore, the motion trajectory of the robotic arm 20 is divided into N segments. At the time of i*T S time, predicting the position deviation and the attitude angle deviation corresponding to the (i + 1)-th segment of the motion trajectory according to the position deviation and the attitude angle deviation corresponding to the i-th segment of the motion trajectory, and correcting the motion of the robotic arm 20 in the (i + 1)-th segment according to the predicted position deviation and the attitude angle deviation corresponding to the (i + 1)-th segment of the motion trajectory, where N = T / T S , T is the correction period, and T S is the period of measurement and data feedback of the optical tracker 30.

[0037] Thus, the motion range of deviation correction is reduced, and the position deviation and the attitude angle deviation on the motion trajectory are corrected in real time, ensuring the accuracy of both the position and the attitude on the motion trajectory.

[0038] As an example, the positioning control device 40 is further configured to: obtain the running speed of the robotic arm 20 based on the position coordinates of the fiducial marker ball 1 measured in real time, and control the robotic arm 20 to stop immediately when the running speed is less than the theoretical speed and the difference exceeds a third set threshold value.

[0039] Specifically, when a collision, system failure, or other situation occurs in the positioning system for radiotherapy, the running speed of the robotic arm 20 may be lagged or incorrect. Therefore, the positioning control device 40 obtains the running speed of the robotic arm 20 based on the position coordinates of the fiducial marker ball 1 measured in real time by the optical tracker 30, and controls the robotic arm 20 to stop immediately when the running speed is less than the theoretical speed and the difference exceeds a third set threshold value.

[0040] Thus, when a collision, system failure, or other situation occurs in the positioning system for radiotherapy, the robotic arm 20 is controlled to stop immediately to prevent losses.

[0041] As an example, the positioning control device 40 is further configured to: store the theoretical data and measurement data of the robotic arm 20 in different treatment postures, obtain a database file, and upgrade the control parameters of the robotic arm 20 according to the database file.

[0042] Specifically, the positioning control device 40 stores the origin positions of the robotic arm 20 in different treatment postures, the actual positions, actual posture angles, and running speeds of the robotic arm 20 to obtain a database file. And upgrade the control parameters of the robotic arm 20 according to the database file. It should be noted that the database file can also be used by devices of the same model.

[0043] In summary, the positioning system for radiotherapy can reduce the influence of position offset, deformation caused by the patient's weight, and mechanical position deviation of the positioning system itself for radiotherapy on the accuracy by obtaining the position deviation and posture angle deviation of the robotic arm based on the position coordinates of the fiducial marker ball, and correcting the positioning of the bedplate by the robotic arm according to the position deviation and posture angle deviation. Thus, on the basis of not affecting the treatment rate and treatment effect, the positioning accuracy of proton heavy ion radiotherapy is improved.

[0044] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0045] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation on the present invention.

[0046] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0047] In the present invention, unless otherwise clearly defined and limited, the terms "mounted", "connected", "coupled", "fixed", etc. shall be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0048] In the present invention, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0049] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as a limitation on the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A positioning system for radiotherapy, characterized in that, The system includes: a bed board, on which a measuring tooling is installed, and a marking ball is installed on the measuring tooling; a robotic arm, which is connected to the bed board and used to adjust the position of the bed board; an optical tracker, which is used to measure the position coordinates of the marking ball in real time; a positioning control device, which is respectively connected to the robotic arm and the optical tracker, and is used to obtain the position deviation and attitude angle deviation of the robotic arm according to the position coordinates of the marking ball, and to correct the positioning of the bed board through the robotic arm according to the position deviation and the attitude angle deviation; a laser tracker target ball is also installed on the measuring tooling, and the positioning control device is also used for: when the robotic arm is at the origin position in different treatment postures, obtaining the position coordinates of the laser tracker target ball through the laser tracker, and obtaining the theoretical position coordinates of the marking ball according to the position coordinates of the laser tracker target ball and the relative position between the laser tracker target ball and the marking ball, and calibrating the error of the optical tracker according to the theoretical position coordinates of the marking ball and the position coordinates of the marking ball measured by the optical tracker; wherein, before obtaining the position deviation and attitude angle deviation of each joint of the robotic arm according to the position coordinates of the marking ball, the positioning control device is also used to correct the position coordinates of the marking ball according to the calibration error of the optical tracker.

2. The system according to claim 1, wherein When obtaining the position deviation and attitude angle deviation of the robotic arm according to the position coordinates of the marking ball, the positioning control device specifically is used for: obtaining the mapping relationship among the world coordinate system, the robotic arm coordinate system and the optical tracker coordinate system, obtaining the actual position and actual attitude angle of the robotic arm according to the mapping relationship and the position coordinates of the marking ball, obtaining the position deviation according to the actual position and the theoretical position of the robotic arm, and obtaining the attitude angle deviation according to the actual attitude angle and the theoretical attitude angle of the robotic arm, wherein the mapping relationship is established according to the position relationship among the marking ball, the robotic arm and the optical tracker.

3. The system according to claim 1, wherein When correcting the positioning of the bed board through the robotic arm according to the position deviation and the attitude angle deviation, the positioning control device specifically is used for: when the position deviation exceeds a first set threshold and the attitude angle deviation exceeds a second set threshold, obtaining the motion deviation of each joint of the robotic arm according to the position deviation and the attitude angle deviation through an inverse kinematics algorithm, and adjusting the motion of the corresponding joint according to the motion deviation to correct the positioning of the bed board.

4. The system according to claim 1, wherein When correcting the positioning of the bed board through the robotic arm according to the position deviation and the attitude angle deviation, the positioning control device specifically is used for: Divide the motion trajectory of the robotic arm into N segments. At the time of i*T S , predict the position deviation and attitude angle deviation corresponding to the (i + 1)-th segment of the motion trajectory based on the position deviation and attitude angle deviation corresponding to the i-th segment of the motion trajectory, and correct the motion of the robotic arm in the (i + 1)-th segment according to the predicted position deviation and attitude angle deviation corresponding to the (i + 1)-th segment of the motion trajectory, where N = T / T S , T is the correction period, and T S is the period of measurement and data feedback of the optical tracker.

5. The system according to claim 1, characterized in that The positioning control device is also used for: obtaining the running speed of the robotic arm according to the real-time measured position coordinates of the marking ball, and controlling the robotic arm to stop immediately when the running speed is less than the theoretical speed and the difference exceeds a third set threshold.

6. The system according to claim 1, wherein The positioning control device is also used for: Store the theoretical data and measured data of the robotic arm in different treatment postures to obtain a database file, and upgrade the control parameters of the robotic arm according to the database file.

7. The system according to claim 1, wherein The measurement tooling includes a first component and a second component. The first component is used to install the laser tracker target ball, and the second component is used to install the marker ball. The first component and the second component are independently arranged and detachable, and the laser tracker target ball and the marker ball are detachably installed.

8. The system according to claim 1, wherein The positioning control device is in wired communication connection with the optical tracker.

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