Isocenter detection method, device, equipment and medium

Abstract

The invention discloses an isocenter detection method and device, equipment and a medium, and relates to the technical field of data processing. The method comprises the steps of collecting a first coordinate set of a plurality of measurement points on the surface of a rack and the surface of a radiation head under the condition that the rack and the radiation head of the radiotherapy equipment are both at initial angles; for each measurement point, according to the first coordinate value of the measurement point, determining a second coordinate value of the measurement point through space coordinate transformation after the radiation head rotates by the target angle; determining a third coordinate value of the common intersection point after the rack rotates by the target angle; determining a fourth coordinate value after the measurement point is rotated by superposing the second coordinate value and the third coordinate value; generating a three-dimensional point cloud data set according to the fourth coordinate values of the plurality of measurement points after rotation; and calculating a minimum enveloping ball enveloping the three-dimensional point cloud data set to determine the center coordinate of the minimum enveloping ball as a dynamic isocenter. Therefore, a more comprehensive isocenter detection method can be obtained, and the reliability and safety of clinical treatment are improved.

Description

Technical Field

[0001] The present application relates to the field of data processing technology, and in particular to a method, device, equipment and medium for detecting an isocenter. Background Art

[0002] Radiotherapy equipment uses ionizing radiation to precisely injure tumor tissue. Its effectiveness relies on a high degree of spatial overlap between the radiation beam and the target tumor volume. The isocenter, the theoretical intersection of the gantry, radiation head, and treatment couch axes, directly determines the effectiveness of the radiotherapy system. Currently, modern precision radiotherapy techniques require the isocenter to be within ±1mm. Larger isocenter errors can lead to deviations in the target dose distribution, potentially causing damage to normal tissue or loss of tumor control.

[0003] In the related art, two isocenter detection methods are usually used. The first is the forward pointer method: the forward pointer method evaluates the isocenter deviation in a two-dimensional plane through the pointer trajectory. Although this method is easy to operate, it only considers the two-dimensional deviation of a single rotation plane and ignores the influence of axial displacement on the isocenter in three-dimensional space. The second is the standard sphere method: the standard sphere method determines the isocenter by measuring the position of the center of the sphere by establishing a spatial coordinate system. Although this method can solve the two-dimensional limitation of the forward pointer method, each measurement can only capture the static isocenter position at a discrete gantry angle, and cannot obtain the dynamic trajectory of the radiotherapy equipment during continuous rotation.

[0004] Therefore, how to determine a more comprehensive isocenter detection method to increase the reliability and safety of clinical treatment has become a technical problem that needs to be solved urgently. Summary of the Invention

[0005] Based on the above problems, the present application provides a method, device, equipment and medium for detecting the isocenter, which can obtain a more comprehensive isocenter detection method, thereby increasing the reliability and safety of clinical treatment.

[0006] The embodiments of this application disclose the following technical solutions:

[0007] In a first aspect, the present application discloses a method for detecting an isocenter, the method comprising:

[0008] When a gantry and a radiation head of the radiotherapy device are both at an initial angle, collecting a first coordinate set of a plurality of measurement points on a surface of the gantry and a surface of the radiation head of the radiotherapy device;

[0009] For each of the measurement points, the following steps are performed: determining, based on the first coordinate value of the measurement point, a second coordinate value of the measurement point after the radiation head is rotated by a target angle through spatial coordinate transformation; determining a third coordinate value of a common intersection point after the frame is rotated by the target angle, wherein the common intersection point is the intersection point of the rotation axis of the frame and the rotation axis of the radiation head; and determining a fourth coordinate value of the measurement point after rotation by superimposing the second coordinate value and the third coordinate value;

[0010] generating a three-dimensional point cloud data set according to the rotated fourth coordinate values ​​of the plurality of measurement points;

[0011] By calculating a minimum envelope sphere that envelops the three-dimensional point cloud data set, the center coordinates of the minimum envelope sphere are determined as the dynamic isocenter.

[0012] Optionally, when the first coordinate value of the measuring point is (x1, y1, z1) and the target angle is θ, the second coordinate value of the measuring point is determined by spatial coordinate transformation to be (x1cosθ+z1sinθ, y1, -x1sinθ+z1cosθ).

[0013] Optionally, when the second coordinate value of the measuring point is (x1cosθ+z1sinθ, y1, -x1sinθ+z1cosθ) and the third coordinate value of the common intersection point is (x2, y2, z2), the fourth coordinate value of the measuring point after rotation is (x1cosθ+z1sinθ+x2, y1+y2, -x1sinθ+z1cosθ+z2).

[0014] Optionally, the initial angle is the gantry rotation angle 0° position, at which the radiation head is located directly above the gantry, and the target angles are selected at equal intervals according to target step lengths and cover a range of 0° to 360°.

[0015] In a second aspect, the present application discloses an isocenter detection device, the device comprising: a set acquisition module, a coordinate determination module, a set generation module, and a center determination module;

[0016] The set acquisition module is configured to acquire a first coordinate set of a plurality of measurement points on the surface of the gantry and the surface of the radiation head of the radiotherapy device when the gantry and the radiation head of the radiotherapy device are both at an initial angle;

[0017] The coordinate determination module is configured to, for each of the measurement points, perform the following steps: determining, through spatial coordinate transformation, a second coordinate value of the measurement point after the radiation head is rotated by a target angle based on the first coordinate value of the measurement point; determining a third coordinate value of a common intersection point after the frame is rotated by the target angle, wherein the common intersection point is the intersection point of the rotation axis of the frame and the rotation axis of the radiation head; and determining a fourth coordinate value of the measurement point after rotation by superimposing the second coordinate value and the third coordinate value;

[0018] The set generating module is configured to generate a three-dimensional point cloud data set according to the rotated fourth coordinate values ​​of the plurality of measurement points;

[0019] The center determination module is used to determine the center coordinates of the minimum envelope sphere as the dynamic isocenter by calculating the minimum envelope sphere that envelops the three-dimensional point cloud data set.

[0020] Optionally, when the first coordinate value of the measuring point is (x1, y1, z1) and the target angle is θ, the second coordinate value of the measuring point is determined by spatial coordinate transformation to be (x1cosθ+z1sinθ, y1, -x1sinθ+z1cosθ).

[0021] Optionally, when the second coordinate value of the measuring point is (x1cosθ+z1sinθ, y1, -x1sinθ+z1cosθ) and the third coordinate value of the common intersection point is (x2, y2, z2), the fourth coordinate value of the measuring point after rotation is (x1cosθ+z1sinθ+x2, y1+y2, -x1sinθ+z1cosθ+z2).

[0022] Optionally, the initial angle is the gantry rotation angle 0° position, at which the radiation head is located directly above the gantry, and the target angles are selected at equal intervals according to target step lengths and cover a range of 0° to 360°.

[0023] In a third aspect, the present application discloses an isocenter detection device, the device comprising: a memory and a processor;

[0024] The memory is used to store programs;

[0025] The processor is used to execute the program to implement each step of the isocenter detection method as described in the first aspect.

[0026] In a fourth aspect, the present application discloses a computer-readable medium having a computer program stored thereon. When the computer program is executed by a processor, the computer program implements the various steps of the isocenter detection method as described in the first aspect.

[0027] Compared with the existing technology, this application has the following beneficial effects:

[0028] The embodiments of the present application disclose a method, apparatus, device and medium for detecting an isocenter, the method comprising: collecting a first coordinate set of multiple measurement points on the surface of the gantry and the surface of the radiation head of the radiotherapy equipment when the gantry and the radiation head are both at an initial angle; for each measurement point, executing: determining, based on the first coordinate value of the measurement point, a second coordinate value of the measurement point after the radiation head is rotated to a target angle through spatial coordinate transformation; determining a third coordinate value of a common intersection point after the gantry is rotated to the target angle, wherein the common intersection point is the intersection point of the rotation axis of the gantry and the rotation axis of the radiation head; determining a fourth coordinate value of the measurement point after rotation by superimposing the second coordinate value and the third coordinate value; generating a three-dimensional point cloud data set based on the fourth coordinate values ​​of the multiple measurement points after rotation; and determining the coordinates of the center of the minimum envelope sphere as the dynamic isocenter by calculating a minimum envelope sphere that envelops the three-dimensional point cloud data set. Therefore, the center point detection method provided in the embodiment of the present application can fully consider the spatial distribution of all measurement points during the rotation of the radiation head, thereby improving the comprehensiveness and accuracy of the isocenter detection, and then enabling the radiotherapy equipment to accurately rotate and adjust around the isocenter during the treatment process, ensuring that the radiation is always focused on the tumor site, reducing misirradiation of surrounding normal tissues, and thus increasing the reliability and safety of clinical treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0030] Figure 1 This is a schematic diagram of the principle of the forward pointer method;

[0031] Figure 2A This is a schematic diagram of a forward pointer method problem;

[0032] Figure 2B This is another problem diagram of the forward pointer method;

[0033] Figure 3A A schematic diagram of a common intersection;

[0034] Figure 3B A schematic diagram of a common intersection point for a forward pointer method;

[0035] Figure 3C A schematic diagram of the common intersection point of a standard sphere method;

[0036] Figure 4A It is a schematic diagram of the isocenter envelope with the gantry at 0 degrees and the radiation head at 0 degrees;

[0037] Figure 4B A schematic diagram of an isocenter envelope with a gantry of 270 degrees and a radiation head of 0 degrees;

[0038] Figure 5 A flowchart of a method for detecting an isocenter provided in an embodiment of the present application;

[0039] Figure 6 A schematic diagram of a rack rotation superposition method provided in an embodiment of the present application;

[0040] Figure 7 A schematic diagram of an isocenter detection device provided in an embodiment of the present application;

[0041] Figure 8 A schematic diagram of a computer-readable medium provided in an embodiment of the present application. DETAILED DESCRIPTION

[0042] As described above, there are two commonly used methods for isocenter detection: the first isocenter detection method is the front pointer method, and the second isocenter detection method is the standard sphere method.

[0043] See also Figure 1 , This figure is a schematic diagram of the principle of the forward pointer method. The specific operation process of the forward pointer method is as follows:

[0044] The first step is to rigidly fix the front pointer to the front end of the radiation head to ensure that the front pointer rotates synchronously with the radiation head. This ensures that during subsequent measurements, the front pointer can accurately reflect the movement state of the radiation head.

[0045] The second step is to rotate the gantry to 180°, so that the radiation head is perpendicular to the treatment table. The position of the treatment table is then adjusted so that the tip of the front pointer comes into contact with the tip of reference pointer 1 (fixed horizontally on the treatment table).

[0046] In the third step, the radiation head is rotated 180° to observe the displacement range of the tip of the front pointer relative to the tip of the reference pointer 1, and the position of the front pointer is adjusted based on the displacement range until the displacement range converges to ±ε (ε is a preset threshold, such as 0.1mm).

[0047] In the fourth step, the calibration process of the third step is repeated at the 90°, 0°, and 270° positions of the frame to ensure that the displacement in the X / Z direction is minimized, thereby eliminating the influence of different gravity directions on the measurement results.

[0048] Step 5: Take the average spatial coordinates of the tip of reference pointer 1 during multiple calibrations as the isocenter, and rotate the gantry plane (e.g. Figure 1 The maximum displacement radius r1 of the circle 1) and the rotation plane of the radiation head (such as Figure 1 The root of the sum of the squares of the maximum displacement radii r2 of circle 2) is taken as the envelope sphere radius.

[0049] However, the forward pointer method has the following three shortcomings:

[0050] First, the forward pointer method assumes that the displacement direction of the gantry rotation plane is orthogonal to the radiation head rotation plane (e.g. Figure 1 As shown). For example, when the maximum displacement radius r1 of the gantry rotation plane is 0.3mm, the maximum displacement radius r2 of the radiation head rotation plane is 0.4mm, and the displacement directions of the gantry rotation plane and the radiation head rotation plane are orthogonal, the theoretical envelope sphere radius R is 0.5mm. However, the measuring tool (usually a micrometer) used in the forward pointer method can only obtain the displacement amplitude, lacks a direction guidance function, and cannot detect the actual spatial angle between the two rotation planes. Since the actual spatial angle cannot be accurately determined, the forward pointer method can only be estimated. This estimation lacks accuracy, and the estimated value may be too large or too small. If the estimated value is too large, it is equivalent to reserving a safety margin to a certain extent; but if the estimated value is too small, it will affect the actual result of the isocenter. See Figure 2A This figure illustrates a problem with the forward pointer method. If the forward pointer method's estimation logic, based on an assumed direction, simply adds the two maximum displacement radii, R = 0.3 + 0.4 = 0.7 mm ≠ 0.5 mm, resulting in a deviation in the isocenter result.

[0051] Second, see Figure 2B , This figure is another schematic diagram of the problem of the forward pointer method. When the rack rotation plane and the radiation head rotation plane are not completely perpendicular and there is a certain angle due to installation errors, elastic deformation caused by the radiation head's own weight, etc., the envelope sphere radius will also change. Figure 2B As shown in the figure, when the gantry rotation plane and the radiation head rotation plane are perpendicular, the envelope sphere diameter is 50, but after a certain angle exists, the envelope sphere diameter becomes 58.17, which leads to deviation in the isocenter result.

[0052] Third, the forward-pointer method measures data only in the rotational plane and fails to consider data in the third direction from a spatial perspective. In practical applications, axial runout variations caused by installation errors, bearing runout, and other factors cannot be ignored, making the forward-pointer method's measurement results incomplete.

[0053] Because the aforementioned drawbacks of the forward-pointer method reduce the reliability and safety of clinical treatment, the standard sphere method has emerged. This method determines the isocenter by measuring the center of a sphere using a spatial coordinate system. While this method overcomes the two-dimensional limitations of the forward-pointer method, each measurement only captures the static isocenter position at discrete gantry angles and cannot capture the dynamic trajectory of the radiotherapy device during continuous rotation.

[0054] Furthermore, it should be noted that both the forward pointer method and the standard sphere method rely on a core geometric feature: the axis of rotation of the gantry and the axis of rotation of the radiation head have a common intersection in three-dimensional space. The common intersection is the intersection of the axis of rotation of the gantry and the axis of rotation of the radiation head. Figure 3A , which is a schematic diagram of a common intersection. Figure 3A The two circles in represent the gantry rotation plane and the radiation head rotation plane respectively. The gantry rotation plane and the radiation head rotation plane each have an axis. The intersection of the two axes is the isocenter, which is also the common intersection point. Figure 3B , the figure is a schematic diagram of a common intersection point of the forward pointer method. Because the forward pointer method requires that the gantry rotation plane and the radiation head rotation plane are orthogonal (90° angle), there is a common intersection point, and the intersection point position is determined by the two-dimensional plane calibration of the mechanical pointer. Figure 3C This figure shows a common intersection point for the standard sphere method. Because the standard sphere method allows for non-orthogonal rotation between the gantry and radiation head planes (such as the actual 85°-95° ​​angle), a common intersection point also exists. The location of this common intersection point is determined by reconstructing the spatial positions of the two axes using 3D imaging.

[0055] Existing methods rely on a single common intersection of the gantry rotation plane and the radiation head rotation plane, which can only reflect the isocenter at a specific angle (for example, gantry 0° and radiation head 0°), and cannot characterize the isocenter drift during the entire dynamic rotation process. If you want to accurately determine the isocenter of the radiation head at various gantry angles, it will take a lot of time and manpower. For example, see Figure 4A , This figure is a schematic diagram of the isocenter envelope at gantry 0 degrees and radiation head 0 degrees. Figure 4A shows the isocenter envelope at gantry 0 degrees and radiation head 0 degrees. Ellipse 1 represents the minimum relative displacement data of gantry rotation, circle 1 represents the minimum relative displacement data of radiation head rotation, and the intersection of the two data represents the center circle of the envelope sphere at this time, which is circle 2. See Figure 4B ,This figure is a schematic diagram of the isocenter envelope with a gantry of 270 degrees and a radiation head of 0 degrees. Figure 4BThe isocenter envelope is shown when the gantry is 270 degrees and the radiation head is 0 degrees. Ellipse 1 remains unchanged, and the size of circle 1 remains unchanged, but the data intersection position changes to the gantry 270 degrees and the radiation head is 0 degrees. At this time, the center circle of the envelope sphere becomes circle 3. The radii of circle 3 and circle 2 are not equal, indicating that the isocenter is different at different angles, and accurate measurement requires a lot of resources.

[0056] In view of this, the embodiments of the present application provide a method, apparatus, equipment and medium for detecting the isocenter. The center point detection method provided in the embodiments of the present application can fully consider the spatial distribution of all measurement points during the rotation of the radiation head, thereby improving the comprehensiveness and accuracy of the isocenter detection, and thus enabling the radiotherapy equipment to accurately rotate and adjust around the isocenter during the treatment process, ensuring that the radiation is always focused on the tumor site, reducing misirradiation of surrounding normal tissues, and thereby increasing the reliability and safety of clinical treatment.

[0057] In order to help those skilled in the art better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of this application.

[0058] See also Figure 5 , which is a flow chart of a method for detecting an isocenter provided in an embodiment of the present application. The method includes:

[0059] S501: When a gantry and a radiation head of a radiotherapy device are both at an initial angle, a first coordinate set of a plurality of measurement points on a surface of the gantry and a surface of the radiation head of the radiotherapy device is collected.

[0060] First, ensure that the gantry and radiation head of the radiotherapy equipment are at their initial angles. Typically, this is the gantry's 0° rotation position (hereinafter referred to as the gantry 0° position), where the radiation head is directly above the gantry.

[0061] It can be understood that, using a standard ball calibration tool, the intersection of the gantry rotation axis (Y axis) and the radiation head rotation axis (Z axis) is set as the coordinate system origin (0,0,0), and a three-dimensional coordinate system is established: the Z axis is the vertical direction, corresponding to the rotation axis direction of the radiation head when the gantry is 0°; the Y axis is the long axis direction of the treatment bed and the gantry rotation axis direction, corresponding to the rotation axis direction of the gantry; the X axis is the horizontal transverse direction.

[0062] In one specific implementation, to ensure the accuracy of the gantry's 0° position, a laser collimator or electronic level can be used for calibration. The calibration requirement is to ensure that the geometric error between the gantry's 0° position and the radiation head's 0° position is ≤ 0.2 mm, thereby reducing measurement errors and improving the accuracy of subsequent calculations.

[0063] Subsequently, with the gantry and radiation head of the radiotherapy equipment at their initial angles, high-precision measurement equipment such as a laser rangefinder, a 3D coordinate measuring machine, or a structured light scanner is used to collect coordinates of multiple measurement points on the surface of the gantry and radiation head of the radiotherapy equipment. This generates a first coordinate set of the multiple measurement points. This first coordinate set is typically stored in a table format, with each row corresponding to the 3D coordinates (x1, y1, z1) of a measurement point.

[0064] It should be noted that in practical applications, multiple measurement points can be evenly distributed across the surfaces of the rack and head using methods such as meshing and curvature-adaptive sampling, depending on the shape and size of the rack and head. The meshing method involves dividing the rack and head surfaces into several regular small regions (such as rectangles or triangles) and selecting a representative measurement point within each small region. The meshing method is suitable for racks and heads with regular shapes and is simple and easy to implement. The curvature-adaptive sampling method increases the density of measurement points in areas with large curvature variations (such as spherical or elliptical surfaces) and reduces the number of measurement points in areas with smaller curvature variations. The curvature-adaptive sampling method is suitable for irregularly shaped racks and heads, enabling more efficient capture of their overall geometric features while reducing redundant data. By evenly distributing multiple measurement points across the rack and head surfaces, the overall spatial position of the rack and head can be prevented from being misjudged due to the concentration of multiple measurement points in localized areas. For example, if the measurement points are concentrated only at the A end of the radiation head, the calculated isocenter may be biased toward the A end, resulting in a large error.

[0065] S502: For each measurement point, execute: determining, based on the first coordinate value of the measurement point, a second coordinate value of the measurement point after the radiation head rotates to a target angle through spatial coordinate transformation; determining a third coordinate value of a common intersection after the rack rotates to the target angle, wherein the common intersection is the intersection of the rotation axis of the rack and the rotation axis of the radiation head; and determining a fourth coordinate value of the measurement point after rotation by superimposing the second coordinate value and the third coordinate value.

[0066] See also Figure 6 This figure is a schematic diagram of a gantry rotation superposition method provided by an embodiment of the present application. First, based on the first coordinate value of the measurement point and the target rotation angle of the radiation head, the second coordinate value of the measurement point after the radiation head rotates by the target angle is calculated using a three-dimensional space rotation matrix.

[0067] In one specific implementation, when the first coordinate value of a measurement point is (x1, y1, z1) and the target angle is θ (e.g., 45°, 90°, 180°, etc.), the second coordinate value of the measurement point can be derived based on the principle of spatial rotation matrix transformation, specifically (x1cosθ + z1sinθ, y1, -x1sinθ + z1cosθ). Here, x1cosθ + z1sinθ represents the new x-coordinate after the rotation, y1 remains unchanged because the rotation occurs in the xz plane, and -x1sinθ + z1cosθ represents the new z-coordinate after the rotation. For example, when the first coordinate value of measurement point A is (1, 2, 3) and the target angle θ is 90°, the second coordinate value of measurement point A is (1×0 + 3×1, 2, −1×1 + 3×0) = (3, 2, -1). It should be noted that the target angle can be selected at intervals of target step size (e.g., 10°, 15°, etc.) and cover the range of 0° to 360°. This allows for comprehensive analysis of the position changes of the measurement points at different rotation angles. This application does not limit the specific target angle.

[0068] Next, the third coordinate of the common intersection point after the gantry is rotated to the target angle is determined. This common intersection point is the intersection of the gantry's rotation axis and the radiation head's rotation axis. At different gantry rotation angles, the common intersection point's position in three-dimensional space changes, so its new coordinate value (i.e., the third coordinate value) must be calculated.

[0069] In one specific implementation, if the design drawings or specifications of the radiotherapy equipment provide the geometric relationship between the gantry and the radiation head, these parameters can be directly used to calculate the third coordinate value (x², y², z²). In another specific implementation, if the equations for the gantry rotation axis and the radiation head rotation axis, as well as their relative positional relationship, are known, the third coordinate value (x², y², z²) can be calculated by solving the equation system. This application does not limit the method for determining the third coordinate value.

[0070] Finally, by superimposing the second coordinate value and the third coordinate value, the final position of the measurement point after rotation (i.e., the fourth coordinate value) is obtained. This step comprehensively considers the effects of the rotation of the radiation head itself and the rotation of the frame.

[0071] In one specific implementation, after the gantry rotates by a target angle, the coordinates of the common intersection point in the gantry coordinate system, namely the third coordinate value (x2, y2, z2), can be determined using data collected by the gantry. The third coordinate value (x2, y2, z2) represents the new position of the initial common intersection point in the gantry coordinate system after the gantry rotation. If the second coordinate value of the measurement point is (x1cosθ+z1sinθ, y1, -x1sinθ+z1cosθ) and the third coordinate value of the common intersection point is (x2, y2, z2), the fourth coordinate value of the measurement point after rotation is (x1cosθ+z1sinθ+x2, y1+y2, -x1sinθ+z1cosθ+z2). The fourth coordinate value of the measurement point after rotation is the sum of the coordinates of the measurement point after the radiation head rotates (the second coordinate value) and the coordinates of the common intersection point in the gantry coordinate system after the gantry rotates (the third coordinate value). The significance of this overlay operation is to convert the rotational position of the measurement point in the radiation head coordinate system to the gantry coordinate system, thereby obtaining the accurate coordinates of the measurement point when the entire device is rotated. For example, if the second coordinate value of measurement point A is (3, 2, -1) and the third coordinate value of the common intersection is (1, 1, 1), the fourth coordinate value of measurement point A after rotation is (3 + 1, 2 + 1, -1 + 1) = (4, 3, 0).

[0072] S503: Generate a three-dimensional point cloud data set according to the rotated fourth coordinate values ​​of the multiple measurement points.

[0073] To fully reflect the positional changes of the measurement points on the radiation head surface in three-dimensional space, it is necessary to integrate the fourth coordinate values ​​of all measurement points after rotation into a unified data set, namely a 3D point cloud dataset. A 3D point cloud dataset is a data structure that represents the geometric characteristics of an object's surface in the form of discrete points. By generating a 3D point cloud dataset, the spatial position and shape changes of the radiation head during dynamic rotation can be intuitively reflected.

[0074] It should be noted that a 3D point cloud data set is usually stored in a specific format, such as a comma-separated value (CSV) file, a text file, etc. This application does not limit the specific storage method.

[0075] S504: Calculating a minimum envelope sphere that envelops the three-dimensional point cloud data set, and determining the center coordinates of the minimum envelope sphere as the dynamic isocenter.

[0076] The minimum enveloping sphere is the smallest sphere that completely covers all points in a 3D point cloud dataset. "Complete coverage" means that every point in the 3D point cloud dataset is contained within or on the sphere's surface; "minimum" requires that the radius of the sphere be as small as possible while still meeting the coverage requirements. The center coordinates of the minimum enveloping sphere are geometrically significant, representing the geometric center of the 3D point cloud dataset. In radiotherapy equipment, these center coordinates are the dynamic isocenter, reflecting the ideal position of the isocenter during continuous rotation.

[0077] In a specific implementation, the minimum envelope sphere may be determined by a genetic algorithm, a simulated annealing algorithm, etc. This application does not limit the specific method for determining the minimum envelope sphere.

[0078] In summary, the embodiments of the present application provide a method for detecting the isocenter. The method for detecting the isocenter provided by the embodiments of the present application can fully consider the spatial distribution of all measurement points during the rotation of the radiation head, thereby improving the comprehensiveness and accuracy of the isocenter detection, and thus enabling the radiotherapy equipment to accurately rotate and adjust around the isocenter during the treatment process, ensuring that the radiation is always focused on the tumor site, reducing misirradiation of surrounding normal tissues, and thereby increasing the reliability and safety of clinical treatment.

[0079] See also Figure 7 , which is a schematic diagram of an isocenter detection device provided in an embodiment of the present application. The isocenter detection device 700 includes: a set acquisition module 701, a coordinate determination module 702, a set generation module 703 and a center determination module 704.

[0080] A set acquisition module 701 is configured to acquire a first coordinate set of a plurality of measurement points on a surface of a gantry and a surface of a radiation head of the radiotherapy device when the gantry and the radiation head of the radiotherapy device are both at an initial angle;

[0081] The coordinate determination module 702 is configured to, for each measurement point, perform the following steps: determining, based on the first coordinate value of the measurement point, a second coordinate value of the measurement point after the radiation head is rotated by a target angle through spatial coordinate transformation; determining a third coordinate value of a common intersection point after the gantry is rotated by the target angle, where the common intersection point is the intersection of the rotation axis of the gantry and the rotation axis of the radiation head; and determining a fourth coordinate value of the measurement point after rotation by superimposing the second coordinate value and the third coordinate value;

[0082] A set generating module 703 is used to generate a three-dimensional point cloud data set according to the rotated fourth coordinate values ​​of the plurality of measurement points;

[0083] The center determination module 704 is configured to determine the coordinates of the center of the minimum enveloping sphere as the dynamic isocenter by calculating the minimum enveloping sphere of the three-dimensional point cloud data set.

[0084] In a specific implementation, when the first coordinate value of the measuring point is (x1, y1, z1) and the target angle is θ, the second coordinate value of the measuring point is determined by spatial coordinate transformation to be (x1cosθ+z1sinθ, y1, -x1sinθ+z1cosθ).

[0085] In a specific implementation, when the second coordinate value of the measuring point is (x1cosθ+z1sinθ, y1, -x1sinθ+z1cosθ) and the third coordinate value of the common intersection point is (x2, y2, z2), the fourth coordinate value of the measuring point after rotation is (x1cosθ+z1sinθ+x2, y1+y2, -x1sinθ+z1cosθ+z2).

[0086] In a specific implementation, the initial angle is the gantry rotation angle 0° position, at which time the radiation head is located directly above the gantry, and the target angles are selected at equal intervals according to the target step length and cover the range of 0° to 360°.

[0087] In summary, the embodiments of the present application provide an isocenter detection device. The isocenter detection device provided in the embodiments of the present application can fully consider the spatial distribution of all measurement points during the rotation of the radiation head, thereby improving the comprehensiveness and accuracy of the isocenter detection, and thus enabling the radiotherapy equipment to accurately rotate and adjust around the isocenter during the treatment process, ensuring that the radiation is always focused on the tumor site, reducing misirradiation of surrounding normal tissues, and thereby increasing the reliability and safety of clinical treatment.

[0088] The embodiments of the present application also provide corresponding isocenter detection equipment and computer-readable media for implementing the isocenter detection method provided in the embodiments of the present application.

[0089] Among them, the isocenter detection device includes a memory and a processor, the memory is used to store instructions or codes, and the processor is used to execute instructions or codes so that the device performs an isocenter detection method of any embodiment of the present application.

[0090] See also Figure 8 , which is a schematic diagram of a computer readable medium provided by an embodiment of the present application. The computer readable medium 800 stores a computer program 811, which implements the above-mentioned Figure 5 Steps of the isocenter detection method.

[0091] It should be noted that in the context of the present application, a machine-readable medium may be a tangible medium that may contain or store a program for use by an instruction execution system, device or equipment or used in conjunction with an instruction execution system, device or equipment. A machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or equipment, or any suitable combination of the foregoing. A more specific example of a machine-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0092] It should be noted that the machine-readable medium mentioned above in this application can be a computer-readable signal medium or a computer-readable storage medium, or any combination of the two. A computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or device, or any combination of the above. More specific examples of computer-readable storage media can include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In this application, a computer-readable storage medium can be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, device, or device. In this application, a computer-readable signal medium can include a data signal propagated in baseband or as part of a carrier wave, which carries computer-readable program code. This propagated data signal can take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. A computer-readable signal medium may also be any computer-readable medium other than a computer-readable storage medium that can transmit, propagate, or transport a program for use by or in conjunction with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium may be transmitted using any suitable medium, including but not limited to wires, optical cables, RF (radio frequency), etc., or any suitable combination thereof.

[0093] The computer-readable medium may be included in the electronic device, or may exist independently without being incorporated into the electronic device.

[0094] Although the subject matter has been described in language specific to structural features and / or methodological logical acts, it should be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are merely example forms of implementing the claims.

[0095] Although several specific implementation details are included in the above discussion, these should not be construed as limiting the scope of this application. Certain features described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented in multiple embodiments individually or in any suitable sub-combination.

[0096] The above description is merely a preferred embodiment of the present application and an illustration of the technical principles employed. Those skilled in the art should understand that the scope of disclosure in this application is not limited to the technical solutions formed by a specific combination of the above-mentioned technical features, but also encompasses other technical solutions formed by any combination of the above-mentioned technical features or their equivalents without departing from the above-mentioned disclosed concepts. For example, a technical solution formed by replacing the above-mentioned features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A method for detecting an isocenter, characterized in that: The method comprises: When a gantry and a radiation head of the radiotherapy device are both at an initial angle, collecting a first coordinate set of a plurality of measurement points on a surface of the gantry and a surface of the radiation head of the radiotherapy device; For each of the measurement points, the following steps are performed: determining, based on the first coordinate value of the measurement point, a second coordinate value of the measurement point after the radiation head is rotated by a target angle through spatial coordinate transformation; determining a third coordinate value of a common intersection point after the frame is rotated by the target angle, wherein the common intersection point is the intersection point of the rotation axis of the frame and the rotation axis of the radiation head; and determining a fourth coordinate value of the measurement point after rotation by superimposing the second coordinate value and the third coordinate value; generating a three-dimensional point cloud data set according to the rotated fourth coordinate values ​​of the plurality of measurement points; By calculating a minimum envelope sphere that envelops the three-dimensional point cloud data set, the center coordinates of the minimum envelope sphere are determined as the dynamic isocenter.

2. The method according to claim 1, characterized in that When the first coordinate value of the measuring point is (x1, y1, z1) and the target angle is θ, the second coordinate value of the measuring point is determined by spatial coordinate transformation to be (x1cosθ+z1sinθ, y1, -x1sinθ+z1cosθ).

3. The method according to claim 2, characterized in that When the second coordinate value of the measuring point is (x1cosθ+z1sinθ, y1, -x1sinθ+z1cosθ) and the third coordinate value of the common intersection point is (x2, y2, z2), the fourth coordinate value of the measuring point after rotation is (x1cosθ+z1sinθ+x2, y1+y2, -x1sinθ+z1cosθ+z2).

4. The method according to claim 1, wherein The initial angle is the gantry rotation angle 0° position, at which the radiation head is located directly above the gantry. The target angles are selected at equal intervals according to the target step length and cover a range from 0° to 360°.

5. A device for detecting an isocenter, characterized in that: The device includes: a set acquisition module, a coordinate determination module, a set generation module and a center determination module; The set acquisition module is configured to acquire a first coordinate set of a plurality of measurement points on the surface of the gantry and the surface of the radiation head of the radiotherapy device when the gantry and the radiation head of the radiotherapy device are both at an initial angle; The coordinate determination module is configured to, for each of the measurement points, perform the following steps: determining, through spatial coordinate transformation, a second coordinate value of the measurement point after the radiation head is rotated by a target angle based on the first coordinate value of the measurement point; determining a third coordinate value of a common intersection point after the frame is rotated by the target angle, wherein the common intersection point is the intersection point of the rotation axis of the frame and the rotation axis of the radiation head; and determining a fourth coordinate value of the measurement point after rotation by superimposing the second coordinate value and the third coordinate value; The set generating module is configured to generate a three-dimensional point cloud data set according to the rotated fourth coordinate values ​​of the plurality of measurement points; The center determination module is used to determine the center coordinates of the minimum envelope sphere as the dynamic isocenter by calculating the minimum envelope sphere that envelops the three-dimensional point cloud data set.

6. The device according to claim 5, characterized in that When the first coordinate value of the measuring point is (x1, y1, z1) and the target angle is θ, the second coordinate value of the measuring point is determined by spatial coordinate transformation to be (x1cosθ+z1sinθ, y1, -x1sinθ+z1cosθ).

7. The device according to claim 6, characterized in that When the second coordinate value of the measuring point is (x1cosθ+z1sinθ, y1, -x1sinθ+z1cosθ) and the third coordinate value of the common intersection point is (x2, y2, z2), the fourth coordinate value of the measuring point after rotation is (x1cosθ+z1sinθ+x2, y1+y2, -x1sinθ+z1cosθ+z2).

8. The device according to claim 5, characterized in that The initial angle is the gantry rotation angle 0° position, at which the radiation head is located directly above the gantry. The target angles are selected at equal intervals according to the target step length and cover a range from 0° to 360°.

9. An isocenter detection device, characterized in that: The device includes: a memory and a processor; The memory is used to store programs; The processor is configured to execute the program to implement each step of the isocenter detection method according to any one of claims 1 to 4.

10. A computer-readable medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, each step of the isocenter detection method according to any one of claims 1 to 4 is implemented.

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