Radiotherapy device image guidance apparatus, guidance method and related devices

Abstract

The application discloses a radiotherapy equipment image guiding device, a guiding method and related equipment, and relates to the technical field of radiotherapy. The device comprises a ray generating module, which is provided with a ray source and is arranged on one side of the isocenter of a treatment room; the ray source is used for moving along a first preset path; the ray source is used for emitting rays, and the rays pass through a patient; a detection and collection module, which is provided with a detector and is arranged on the other side of the isocenter of the treatment room and is distributed opposite to the ray source along the isocenter; the detector is used for moving along a second preset path, is used for collecting the rays after passing through the patient, and is used for converting the rays into corresponding projection images; and a registration module, which is used for registering the projection images with a planning CT image to calculate a positioning deviation by executing a first registration mode or a second registration mode; the first preset path and the second preset path are both straight lines, and the adaptability, the precision and the stability of radiotherapy are improved.

Description

Technical Field

[0001] This invention relates to the field of radiotherapy technology, and in particular to image guidance devices, guidance methods and related equipment for radiotherapy equipment. Background Technology

[0002] In proton radiotherapy, image guidance is a crucial step in ensuring treatment precision. Its core lies in achieving precise patient positioning and target localization through accurate imaging. Currently, the mainstream image guidance methods primarily rely on X-ray and CT technologies, but both have limitations: X-ray guidance, while achieving isocentric imaging with high efficiency, suffers from two-dimensional imaging characteristics that make it difficult to clearly display three-dimensional anatomical structures, hindering anatomical analysis of the tumor and surrounding tissues and accurate assessment of tumor size changes and the reliability of registration results; CT guidance, while providing three-dimensional images and supporting detailed analysis and high-precision registration of the tumor and surrounding tissues, requires the treatment bed to support the patient as they move between the CT scan position and the treatment positioning position. During this process, mechanical motion errors of the treatment bed and the patient's voluntary / physiological movements (such as breathing and body movements) can affect the efficiency and precision of image guidance.

[0003] To address these issues, some manufacturers have introduced isocentric in-situ CBCT scanning solutions, which combine 3D imaging with isocentric scanning to balance the stability of 3D anatomical visualization and in-situ guidance. However, existing isocentric in-situ CBCTs all employ a circular scanning mode, requiring a ring-shaped gantry arranged around the center of the treatment room. Due to limitations in the spatial layout of some radiotherapy equipment (such as room size and interference from existing mechanical structures) and installation conditions, they cannot be adapted for use on most devices. This means that these devices still rely on 2D X-ray or non-isocentric CT guidance, making it difficult to balance guidance accuracy, anatomical analysis requirements, and equipment compatibility. Furthermore, existing isocentric in-situ CBCTs struggle to achieve a precise balance between imaging performance and radiation safety. Summary of the Invention

[0004] The purpose of this invention is to provide an image guidance device, guidance method and related equipment for radiotherapy equipment. Through linear trajectory scanning, not only isocentric in-situ scanning can be performed, but also three-dimensional imaging can be obtained, which greatly improves the accuracy and stability of radiotherapy; at the same time, X-ray two-dimensional imaging can be realized, and radiotherapy image guidance can be achieved efficiently.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] In a first aspect, the present invention provides an image-guided device for radiotherapy equipment, the device comprising:

[0007] A radiation generating module, equipped with a radiation source, is positioned on one side of the center of a treatment room, etc.; the radiation source is used to move along a first preset path; the radiation source is used to emit radiation, which passes through the patient;

[0008] The detection and acquisition module is equipped with a detector, which is located on the other side of the center of the treatment room and is distributed relative to the radiation source along the center; the detector is used to move along a second preset path to collect the radiation after passing through the patient and convert it into a corresponding projection image.

[0009] The registration module is used to register the projected image with the planned CT image by executing a first registration mode or a second registration mode to calculate the positioning deviation.

[0010] Both the first preset path and the second preset path are straight lines.

[0011] Preferably, both the first preset path and the second preset path are vertical straight lines along the direction of gravity; the detector moves in the opposite direction to the radiation source.

[0012] Preferably, the device acquires the projected image by means of:

[0013] The X-ray source is moved along the first preset path until the end of the journey, and at the preset position on the moving trajectory, the patient's projected image is acquired by the detector.

[0014] When the radiation source moves along the first preset path, the central axis of the radiation source is always aligned with the center of the treatment room. When the radiation source moves a first preset distance to its preset position, the detector is moved in the opposite direction along the second preset path by a second preset distance so that the radiation beam and the receiving surface of the detector are aligned so as to collect the patient's projected image.

[0015] Preferably, the first registration mode includes:

[0016] The X-ray source is moved to multiple locations along the entire first preset path to acquire multiple projection images;

[0017] CBCT images are generated by 3D reconstruction of multiple projection images;

[0018] The CBCT images are registered with the planned CT images, the positioning deviation is calculated, and parameters for treatment bed correction are output.

[0019] Optionally, the second registration mode includes:

[0020] Projected images are acquired at any position along the trajectory of the moving X-ray source;

[0021] The projected image is registered with the DRR image generated from the planned CT image to obtain the first registration result;

[0022] Based on the first registration result, calculate the positioning deviation and output the parameters for correction of the treatment bed.

[0023] Optionally, the second registration step includes:

[0024] Projected images are acquired at at least two locations along the trajectory of the radiation source.

[0025] Obtain DRR images corresponding to each of the projected images generated from the planned CT images;

[0026] Each of the projected images is registered with its corresponding DRR image to obtain multiple first registration results.

[0027] Based on multiple first registration results, the setup deviation is calculated and parameters for treatment bed correction are output.

[0028] In a second aspect, the present invention provides an image-guided method for radiotherapy equipment, the method comprising:

[0029] A radiation source positioned on one side of the center of the treatment room is controlled to move along a first preset path, emitting radiation during the movement, and the radiation passes through the patient;

[0030] The detector, which is located on the other side of the center of the treatment room and is distributed relative to the radiation source along the center, moves along a second preset path to collect the radiation after passing through the patient and convert it into a corresponding projection image; wherein, both the first preset path and the second preset path are straight lines.

[0031] The projected image is processed and registered with the planned CT image to calculate the positioning deviation;

[0032] Both the first preset path and the second preset path are straight lines.

[0033] Preferably, both the first preset path and the second preset path are vertical straight lines along the direction of gravity; the detector moves in the opposite direction to the radiation source.

[0034] Preferably, the projected image is acquired by means of:

[0035] The X-ray source is moved along the first preset path until the end of the journey, and at the preset position on the moving trajectory, the patient's projected image is acquired by the detector.

[0036] When the radiation source moves along the first preset path, the central axis of the radiation source is always aligned with the center of the treatment room. When the radiation source moves a first preset distance to its preset position, the detector is moved in the opposite direction along the second preset path by a second preset distance so that the radiation beam and the receiving surface of the detector are aligned so as to collect the patient's projected image.

[0037] Optionally, the registration of the projected image with the planned CT image is achieved by executing a first registration mode, including:

[0038] The X-ray source is moved to multiple locations along the entire first preset path to acquire multiple projection images;

[0039] CBCT images are generated by 3D reconstruction of multiple projection images;

[0040] The CBCT images are registered with the planned CT images, the positioning deviation is calculated, and parameters for treatment bed correction are output.

[0041] Optionally, the registration of the projected image with the planned CT image is achieved by executing a second registration mode, including:

[0042] Projected images are acquired at any position along the trajectory of the moving X-ray source;

[0043] The projected image is registered with the DRR image generated from the planned CT image to obtain the first registration result;

[0044] Based on the first registration result, calculate the positioning deviation and output the parameters for correction of the treatment bed.

[0045] Optionally, the registration of the projected image with the planned CT image is achieved by executing a second registration mode, including:

[0046] Projected images are acquired at at least two locations along the trajectory of the radiation source.

[0047] Obtain DRR images corresponding to each of the projected images generated from the planned CT images;

[0048] Each of the projected images is registered with its corresponding DRR image to obtain multiple first registration results.

[0049] Based on multiple first registration results, the setup deviation is calculated and parameters for treatment bed correction are output.

[0050] Thirdly, the present invention provides a radiotherapy system, comprising:

[0051] The image guidance device for radiotherapy equipment described in any embodiment of the present invention.

[0052] Fourthly, the present invention provides an electronic device, the electronic device including a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the steps of any of the methods of the present invention or the functions of the apparatus of the present invention.

[0053] Fifthly, the present invention provides a computer-readable storage medium storing computer instructions, wherein when a computer reads the computer instructions, the computer executes the steps of any of the methods described in the present invention.

[0054] Compared with existing technologies, the beneficial effects of this invention include at least the following: It adopts an isocentric in-situ linear CBCT scanning design, eliminating the need for a circular track and solving the problem that some radiotherapy equipment cannot install a circular CBCT system due to space or structural limitations. While maintaining the core advantages of isocentric imaging, it is compatible with more models, expanding the application range of precise image guidance. It can acquire multiple projection images through linear movement to reconstruct a three-dimensional CBCT, solving the problem that traditional two-dimensional X-ray images are not conducive to anatomical analysis and tumor size change assessment, providing doctors with complete three-dimensional anatomical information; it can also flexibly switch to two-dimensional imaging mode, quickly completing guidance through X-ray images from two positions, balancing high precision requirements with treatment efficiency. Through a projection quantity decision model and a step length dynamic adjustment model, the acquisition scheme is optimized based on individualized parameters such as patient target area characteristics and physiological movement, ensuring coverage of key structures while controlling radiation dose, meeting the precise guidance needs of complex cases while complying with radiation protection principles.

[0055] In summary, this solution, by overcoming equipment limitations and employing an innovative design of "in-situ scanning + 3D / 2D dual-mode imaging," overcomes the shortcomings of traditional X-ray and non-in-situ CT guidance, providing more reliable and flexible image guidance support for radiotherapy, and ultimately improving treatment accuracy and safety. Attached Figure Description

[0056] Figure 1 This is a schematic diagram of the image guidance device for radiotherapy equipment according to an embodiment of the present invention;

[0057] Figure 2 This is a schematic diagram showing the position and movement direction of the image guidance device component of the radiotherapy equipment according to an embodiment of the present invention;

[0058] Figure 3 This is a schematic diagram of an image-guided radiotherapy device according to an embodiment of the present invention;

[0059] Figure 4 This is a schematic diagram of a radiotherapy system according to an embodiment of the present invention. Detailed Implementation

[0060] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided to make the invention more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and therefore repeated descriptions of them will be omitted.

[0061] The terms used to express position and direction in this invention are illustrated with reference to the accompanying drawings, but changes can be made as needed, and all such changes are included within the scope of protection of this invention.

[0062] See attached document Figure 1 and attached Figure 2 An image-guided device for radiotherapy equipment, the device comprising:

[0063] A radiation generating module, equipped with a radiation source, is positioned on one side of the center of a treatment room, etc.; the radiation source is used to move along a first preset path; the radiation source is used to emit radiation, which passes through the patient; the imaging source is an X-ray source;

[0064] The detection and acquisition module is equipped with a detector, which is located on the other side of the center of the treatment room and is distributed relative to the radiation source along the center. The detector is used to move along a second preset path to collect the radiation after passing through the patient and convert it into a corresponding projection image, i.e., an X-ray image.

[0065] The registration module is used to register the projected image with the planned CT image by executing a first registration mode or a second registration mode to calculate the positioning deviation.

[0066] Both the first preset path and the second preset path are straight lines.

[0067] The first and second preset paths are not on the movement path of the treatment head and are not parallel to the movement path of the treatment head; the detector moves in the opposite direction to the radiation source, and the central axis of the detector and the central axis of the radiation source both pass through the center of the treatment room; the detector and the radiation source move before the treatment head moves around the patient to perform treatment.

[0068] The working principle of the above technical solution is as follows:

[0069] If the walls of the treatment room are load-bearing and have the necessary positioning capabilities, the radiation source and detector can be directly installed on the walls on both sides of the isocenter, ensuring the stability of their movement trajectory through wall fixation. If the walls are not suitable for installation, independent mounting brackets (such as floor-mounted brackets or ceiling-mounted brackets) can be used. The mounting brackets must be rigidly connected to the floor or ceiling of the treatment room to ensure that the radiation source and detector will not be displaced due to vibration or load during movement.

[0070] From the perspective of spatial distance from the isocenter, the X-ray source and the isocenter need to maintain a preset working distance (usually determined based on the X-ray beam energy, penetration capability, and detector size). This distance must ensure that the X-ray beam can still be effectively received by the detector and the image is clear after passing through the isocenter area (patient target area). If the distance is too close, the X-ray beam coverage may be insufficient, and if the distance is too far, the quality of the projected image may be affected by X-ray attenuation.

[0071] The X-ray source and detector can be arranged symmetrically with respect to the isocenter: that is, the straight-line distance from the X-ray source to the isocenter is equal to the straight-line distance from the detector to the isocenter, and the three (X-ray source center - isocenter - detector center) are on the same straight line. The advantage of this symmetrical distribution is that when the X-ray source moves along the first preset path, the detector only needs to move in the opposite direction along the second preset path by the same distance to keep aligned with the X-ray beam, simplifying the movement control logic. At the same time, the symmetrical layout can ensure that the divergence angle of the X-ray beam after passing through the isocenter always matches the detector receiving surface under different movement positions, reducing the geometric distortion of the projected image.

[0072] Of course, in practical applications, if the space of the treatment room is limited (such as the presence of obstacles on one side of the wall), an asymmetrical distribution (i.e., the distances from the radiation source and the detector to the isocenter are different) can also be adopted. However, the algorithm of the motion control module needs to be used to compensate for this and ensure that the moving distance of the detector and the moving distance of the radiation source are in a suitable ratio. This will still maintain the alignment of the radiation beam and the receiving surface, thus balancing installation flexibility and imaging accuracy.

[0073] In the initial state, the central axis of the radiation source is aligned with the isocenter, and the detector receiving surface is aligned with the radiation beam to ensure that the radiation beam is effectively received by the detector after passing through the isocenter region (patient target area).

[0074] The radiation source moves along a first preset straight path, maintaining its central axis aligned with the isocenter and continuously emitting radiation throughout the movement; the detector moves along a second preset straight path in the opposite direction to the radiation source, keeping the receiving surface aligned with the radiation beam at the corresponding position, collecting the radiation after it passes through the patient and converting it into a projection image (multiple projections can be collected at multiple discrete positions along the movement trajectory).

[0075] The registration module processes the acquired projection images (such as generating CBCT images through 3D reconstruction or directly using 2D projection), registers them with the planned CT images, calculates patient positioning deviations, and finally outputs correction parameters for treatment bed adjustment to ensure that the particle beam accurately irradiates the target area during treatment.

[0076] The effects of the above technical solution are as follows:

[0077] Throughout the entire movement of the X-ray source, the central axis is kept aligned with the isocenter. The detector moves in the opposite direction to the X-ray source along a second preset straight path, keeping the receiving surface aligned with the X-ray beam at the corresponding position. This achieves isocenter in-situ image acquisition, avoiding treatment bed errors and patient voluntary movement interference caused by patient movement during non-isocenter CT guidance, and significantly improving the accuracy and stability of image guidance.

[0078] The X-ray source and detector move along a straight path (rather than scanning in a circular arc), resulting in a simple mechanical structure and small footprint. This makes it suitable for radiotherapy equipment that cannot be installed with a circular CBCT system due to space or structural limitations, thus broadening the application scenarios of isocentric 3D image-guided technology.

[0079] It supports multi-frame projection image acquisition and 3D reconstruction (CBCT), providing 3D anatomical information and solving the problem of difficult anatomical analysis in 2D X-ray guidance; at the same time, it is compatible with dual-position 2D projection mode to meet the guidance needs of different treatment scenarios, and is highly flexible.

[0080] The linear scanning path allows for flexible adjustment of the number and angle distribution of projection acquisitions, ensuring sufficient projection to guarantee the accuracy of 3D reconstruction while avoiding unnecessary redundant projections, thus reducing the patient's radiation dose and conforming to the principle of minimum radiation in radiotherapy. The linear movement mechanism is easy to integrate with existing radiotherapy equipment, reducing modification and maintenance costs.

[0081] In one possible implementation, the device further includes:

[0082] The motion control module is used to drive the movement of the X-ray source and detector, as well as the angular rotation of the X-ray source.

[0083] As the core driving and coordination unit of the device, the motion control module's functions can be refined into a three-layer architecture of precise driving, real-time sensing, and intelligent adaptation. In one possible implementation, this specifically includes:

[0084] Drive execution components: Equipped with a high-precision linear motor (driving the X-ray source along a first preset path and the detector along a second preset path) and a servo rotary motor (driving the X-ray source to rotate around its central axis to adjust the emission angle), the motor control accuracy reaches 0.1mm (movement) and 0.1° (rotation), ensuring the accuracy of motion response.

[0085] The sensing feedback component integrates a grating ruler (to monitor the actual displacement of the X-ray source and detector in real time), an angle encoder (to record the rotation angle of the X-ray source), and a laser positioner (to assist in calibrating center alignment deviations). The feedback data sampling frequency is no less than 1kHz, providing real-time data for closed-loop control.

[0086] Control algorithm unit: Built-in motion coordination algorithm (ensures the synchronization of the X-ray source and detector moving in opposite directions, with a time difference of ≤5ms), angle compensation algorithm (dynamically calculates the required rotation angle based on the distance the X-ray source moves, ensuring that the central axis is always aligned with the center), and error correction algorithm (adjusts the motor output in real time based on sensor feedback data to compensate for mechanical backlash or external disturbances).

[0087] The execution steps of the motion control module include:

[0088] The system receives acquisition instructions from the registration module (such as the number of projections and their location distribution), and plans the movement trajectory of the X-ray source, the reverse trajectory of the detector, and the rotation angle sequence of the X-ray source in combination with preset path parameters (length and direction). For example, when the X-ray source moves 100mm along the vertical path, it needs to rotate by an angle θ to compensate for the displacement of the central axis. θ is calculated by the geometric relationship θ = arctan(movement distance / distance from the source to the isocenter).

[0089] Drive execution: Based on the planning results, drive signals are sent to the linear motor and rotary motor to control the X-ray source to move along the first path and the detector to move in the opposite direction along the second path. At the same time, the X-ray source is driven to rotate to the target angle to ensure that the central axis of the X-ray beam always passes through the isocenter.

[0090] Real-time feedback and correction: During the motion, the grating ruler and angle encoder continuously collect actual displacement and angle data. If the deviation from the planned value exceeds the threshold (e.g., displacement deviation > 0.5mm, angle deviation > 0.5°), the control algorithm immediately adjusts the motor output (e.g., increase / decrease the driving torque) until the deviation returns to the allowable range.

[0091] Linked trigger acquisition: When the X-ray source and detector reach the preset acquisition position and the motion deviation is stable within the threshold, a trigger signal is sent to the detection and acquisition module to synchronously start the X-ray emission and projection image acquisition, ensuring the spatial position accuracy of each projection.

[0092] In one possible implementation, the first preset path and the second preset path are parallel to each other.

[0093] The parallelism of the two paths ensures that the movement directions of the X-ray source and the detector remain consistent (e.g., both along the vertical direction or both along a specific horizontal direction), providing a geometric basis for their synchronous reverse movement. When the X-ray source moves along the first path, the detector moves in the opposite direction along the second path. Because the paths are parallel, their relative displacements are always within the same plane, allowing for synchronization through simple linear control (e.g., the X-ray source moves upward by x distances, and the detector moves downward by x distances). This avoids the complex coordinate transformation calculations required for non-parallel paths and significantly reduces the algorithmic complexity of the movement control module.

[0094] From the perspective of beam alignment, a parallel path, combined with the constraint that "the central axis of the X-ray source is always aligned with the isocenter," ensures that the relative angle between the beam divergence direction and the detector receiving surface remains stable. For example, when the X-ray source moves along a vertical path parallel to the direction of gravity, the central axis of its emitted conical beam always points to the isocenter, while the detector moves in the opposite direction along a parallel vertical path, ensuring that it remains coplanar with the beam divergence surface. This stability avoids "tilting misalignment" between the beam and the detector receiving surface caused by non-parallel paths, reduces geometric distortion of the projected image, and provides higher-quality raw data for subsequent 3D reconstruction (CBCT) or 2D registration (X-ray).

[0095] Furthermore, the parallel straight path design makes the device more adaptable to the spatial layout of different treatment rooms. Compared to circular paths, the mechanical structure (such as guide rails and sliders) of straight paths is simpler, and the path length can be flexibly adjusted according to the site dimensions (such as shortening or lengthening the guide rails), making it particularly suitable for radiotherapy equipment in space-constrained environments. Simultaneously, the movement range of the X-ray source and detector under a parallel path can be set independently (while maintaining a reverse synchronous relationship). This not only meets the scanning needs of patients with large tumors (by increasing the path length to expand the imaging range) but also reduces ineffective movement during scanning of small target areas (such as head and neck tumors) by shortening the path, further improving operational efficiency.

[0096] See attached document Figure 2 In one possible implementation, the first preset path and the second preset path are parallel to each other and are both vertical straight lines along the direction of gravity; the detector moves in the opposite direction to the radiation source.

[0097] Projection acquisition is triggered at multiple discrete height positions (e.g., every 10 mm or at intervals set according to clinical needs) along the vertical movement trajectory of the X-ray source and detector. Since the path is along the direction of gravity, the patient's body naturally stretches due to gravity, reducing possible postural swaying during horizontal movement; at the same time, multi-position acquisition in the vertical direction can cover different anatomical layers (e.g., the upper and lower lobes of the thoracic cavity, the liver area and pelvis of the abdominal cavity), providing projection images of the entire target area for three-dimensional reconstruction.

[0098] Vertical movement along the direction of gravity eliminates the need for patients to exert additional force for postural adjustment, allowing their bodies to naturally conform to the treatment bed. This reduces voluntary or involuntary swaying that may occur during horizontal movement (such as horizontal body displacement caused by breathing), making it particularly suitable for patients with thoracic and abdominal tumors and reducing projection image errors caused by changes in body position.

[0099] Vertical straight paths allow for the direct use of the treatment room's vertical space (such as the height from ceiling to floor) to arrange guide rails, eliminating the need for a large horizontal movement area and resulting in a more compact mechanical structure. For space-constrained radiotherapy rooms (such as scenarios with sufficient ceiling height but limited horizontal width), this design maximizes the use of existing space and reduces site modification costs during equipment installation.

[0100] Vertical movement in the direction of gravity ensures that the relative positions of the X-ray source and detector are always distributed along the longitudinal axis of the human body. The path of the X-ray beam as it passes through the patient more closely follows the natural orientation of the anatomical structure (such as vertical layers from head to toe). Compared to a horizontal path, this layout reduces scattering interference when the X-ray beam passes through high-density tissues such as bones and cavities. At the same time, combined with reverse synchronous movement, it further reduces projection geometric distortion caused by path deviation and improves the clarity of the target area in 3D reconstruction.

[0101] For tumors in different locations such as the head and neck (small vertical range) and the body (large vertical range), the vertical path movement range can be flexibly adjusted (e.g., shorten the movement distance for head and neck scans and extend the distance for body scans). This ensures sufficient coverage of key target areas while avoiding wasted time due to ineffective movement, thus balancing imaging efficiency and radiation safety.

[0102] In one possible implementation, the device acquires the projected image by:

[0103] The radiation source is moved along the first preset path until the end of the journey. At the preset position on the moving trajectory, the detector acquires the patient's projected image, i.e., the X-ray image.

[0104] When the radiation source moves along the first preset path, the central axis of the radiation source is always aligned with the center of the treatment room. When the radiation source moves a first preset distance to the first preset position, the detector is moved in the opposite direction along the second preset path by a second preset distance, either synchronously or asynchronously, so that the radiation beam and the receiving surface of the detector are aligned together to collect the patient's projected image. The first preset distance may be equal to or not equal to the second preset distance.

[0105] The X-ray source and detector are distributed along first and second preset straight paths (such as vertical parallel paths or parallel paths at other angles), respectively. Their initial positions ensure that the central axis of the X-ray source is aligned with the isocenter of the treatment room (the central axis of the X-ray beam always coincides with the isocenter, or the deviation of the central axis of the X-ray beam from the isocenter never exceeds a deviation threshold), ensuring that the X-ray beam dispersion range covers the isocenter and the treatment area where the patient is located. The detector's receiving surface is aligned with the X-ray beam to ensure complete acquisition of the X-ray projection image passing through the patient. Based on the path spatial layout (such as whether the distances from the X-ray source and detector to the isocenter are symmetrical), an adaptation relationship is set between the first preset distance (the distance the X-ray source moves) and the second preset distance (the distance the detector moves in the opposite direction). If the distances to the isocenter are equal (symmetrical layout), the distances are set to be equal; if the distances are unequal (asymmetrical layout), the distance ratio is set through geometric conversion. The patient's treatment site is located at the isocenter.

[0106] On the trajectory of the X-ray source, when it reaches a preset discrete position (such as the starting point, midpoint, end point of the path, or a key height set according to clinical needs), the acquisition command is triggered: the X-ray source emits X-rays that pass through the patient, and the detector synchronously receives the X-rays and converts them into projection images, i.e., X-ray images. Because the distance coordination mechanism adapts to the path layout, even in asymmetrical paths, the X-ray beam at each acquisition position can accurately cover the isocentric area, and the detector receives the X-rays without deviation, ensuring the consistency of multiple projections in the spatial coordinate system.

[0107] In one possible implementation, the total travel of the first preset path is determined based on the distribution range of the patient's target area and key anatomical structures, ensuring that the movement of the radiation source from the starting position to the ending position along the direction of movement enables the radiation beam to completely cover the target area.

[0108] The position at the end of the radiation source's travel is set collaboratively using radiotherapy planning parameters, patient and target area characteristics, and equipment physical constraints.

[0109] Radiotherapy planning parameters: Based on the three-dimensional coordinate range of the target area in the planned CT image (such as the maximum / minimum coordinate value in the Z-axis direction), extend outward by 5-10mm as the basic travel boundary;

[0110] Patient and target area characteristics: Combine the patient's body size (body thickness, height) and the range of target area movement (such as the tumor displacement amplitude caused by respiration) to correct the basic travel boundary. The correction amount is 1-2 times the maximum displacement of the target area.

[0111] Equipment physical constraints: The upper limit is set by the mechanical travel limit of the equipment (such as the maximum range of the hardware for vertical movement of the X-ray source) to ensure that the end of the set travel does not exceed the safe operating range of the equipment.

[0112] In one possible implementation, the registration module performs a first registration mode (three-dimensional registration mode), which involves reconstructing a three-dimensional CBCT image through multi-position projection and then registering it with the planned CT scan, including:

[0113] The X-ray source is moved to multiple locations along the entire first preset path to acquire multiple projection images;

[0114] CBCT images are generated by 3D reconstruction of multiple projection images;

[0115] The CBCT images are registered with the planned CT images, the positioning deviation is calculated, and parameters for treatment bed correction are output.

[0116] The working principle of the above technical solution is as follows:

[0117] The radiation source moves along a first preset path, acquiring projection images at multiple discrete locations (the number dynamically adjusted according to clinical needs, such as 10-30). These locations cover the entire path, ensuring that radiation attenuation information of the patient's target area and surrounding tissues is obtained from different angles (based on the perspective of the straight-line trajectory formed by the movement of the radiation source).

[0118] The acquired projection images are first preprocessed, including noise removal (through Gaussian filtering or median filtering), correction of radiation hardening effect (correction of high-energy radiation attenuation deviation based on a preset calibration curve), and unification of spatial coordinates (establishing a coordinate system with the center of the treatment room as the origin and marking the position and angle parameters of the radiation source corresponding to each projection), to provide high-quality raw data for subsequent reconstruction.

[0119] Three-dimensional reconstruction is performed on multiple preprocessed projection images, for example, using filtered back projection (FBP) or iterative reconstruction algorithms (such as ART and SIRT). During reconstruction, with the isocenter as the spatial reference, projection images at different angles are back-projected onto a three-dimensional voxel grid. The density value of each voxel is calculated by weighting its corresponding ray attenuation value in all projection images, ultimately generating a three-dimensional CBCT image consistent with the patient's actual anatomical structure (resolution typically reaching 0.5-1 mm). Because the projection images come from isocenter in-situ scanning, the reconstructed CBCT image is spatially aligned with the treatment location, avoiding positional deviations caused by non-isocenter scanning.

[0120] The registration process uses the planned CT images as a reference (including clinical markers such as the tumor target area and organs at risk), and can achieve accurate matching through the following steps:

[0121] Coarse registration is performed using image grayscale features (such as bone density differences and soft tissue contours) or anatomical markers (such as vertebral body edges and metal markers) to quickly align the approximate positions of CBCT and planning CT images, reducing the computational load for subsequent fine registration.

[0122] A rigid registration algorithm (for rigid structures such as the head and neck) or an elastic registration algorithm (for deformable regions such as the chest and abdomen) is employed. By iteratively optimizing the translation (X, Y, Z axes) and rotation (pitch, roll, rotation) parameters in three-dimensional space, the differences in anatomical structure edges and density distribution deviations between CBCT and planning CT images are minimized. Specifically, the normalized mutual information (measuring the correlation of gray-level distributions between the two images) reaches its maximum value, and the mean square error (measuring the density difference of corresponding voxels) reaches its minimum value. The final registration result must meet clinical acceptance criteria, such as a target area center overlap error ≤1mm and an organ contour overlap ≥95%, which serves as a quantitative indicator of the "optimal" registration state.

[0123] Deviation verification: The deviation of the target area center is manually checked by the doctor or automatically detected to ensure that the registration result meets clinical requirements (usually the error should be ≤1mm).

[0124] After registration, the module calculates the three-dimensional positioning deviation (including translation and rotation parameters) of the patient's current position relative to the planned CT image and converts it into adjustment commands for the treatment bed (such as moving +2mm along the X-axis and rotating -0.5° around the Y-axis), which are then output to the treatment control system. After the treatment bed completes the correction according to the commands, the patient's target area is precisely aligned with the irradiation position in the radiotherapy plan, ensuring accurate delivery of the particle beam during treatment.

[0125] The entire process relies on 3D data acquired in situ at the isocenter, achieving spatial consistency throughout the entire process from imaging to registration. This effectively eliminates positional errors from non-isocenter scanning and significantly improves the accuracy and efficiency of setup verification.

[0126] In one possible implementation, the registration module performs a second registration mode (i.e., a two-dimensional registration mode), directly registering the projected image with the DRR image generated by the planned CT scan, including:

[0127] Projected images are acquired at any position along the trajectory of the moving X-ray source;

[0128] The projected image is registered with the DRR image generated from the planned CT image to obtain the first registration result;

[0129] Based on the first registration result, calculate the positioning deviation and output the parameters for correction of the treatment bed.

[0130] In one possible implementation, the first registration result includes the similarity between the projected image and the DRR image (such as mutual information, normalized cross-correlation coefficient, etc.);

[0131] The patient's positioning deviation is determined based on the similarity, and parameters for correction of the treatment bed are output; the positioning deviation includes 6 degrees of freedom deviation (including translation of the X, Y, and Z axes and rotation around the three axes).

[0132] In one possible implementation, determining the patient's positioning deviation based on the similarity includes:

[0133] Establish a mapping relationship between the combination of placement parameters and the similarity, wherein the combination of placement parameters includes translation parameters and / or rotation parameters;

[0134] Search for the optimal combination of placement parameters in the mapping relationship and determine it as the placement deviation.

[0135] In this process, a mapping relationship is established by iteratively adjusting the combination of placement parameters (translation and rotation parameters) and calculating the corresponding similarity.

[0136] The above technical solution offers the following advantages: it supports the acquisition of projection images at any position along the trajectory of the radiation source, eliminating the need for fixed angles and adapting to various radiotherapy scenarios (such as emergency positioning or special target locations); by iteratively adjusting positioning parameters and establishing a parameter-similarity mapping, it can accurately locate the parameter combination that best matches the projection image with the DRR, ensuring the accuracy of the 6-DOF positioning deviation calculation; the two-dimensional registration process based on a single projection image is simple and faster than three-dimensional reconstruction (such as CBCT), reducing patient positioning time and lowering the risk of radiation exposure; the output 6-DOF deviation can directly drive mainstream treatment beds to complete multi-dimensional position corrections, adapting to common clinical needs for precise radiotherapy (such as head and neck, thoracic and abdominal tumors).

[0137] In one possible implementation, the registration module performs a second registration mode, including:

[0138] Projected images are acquired at at least two locations along the trajectory of the radiation source.

[0139] Obtain DRR images corresponding to each of the projected images generated from the planned CT images;

[0140] Each of the projected images is registered with its corresponding DRR image to obtain multiple first registration results.

[0141] Based on multiple first registration results, the setup deviation is calculated and parameters for treatment bed correction are output.

[0142] By using projected images from at least two different locations, a richer spatial perspective (such as frontal, lateral, and oblique views) is covered, overcoming the limitations of single-view projection in three-dimensional spatial information and reducing directional ambiguity in positioning deviation calculations. Multiple sets of registration results mutually constrain each other, reducing registration errors caused by noise, artifacts, or overlapping anatomical structures in a single image, thus improving the reliability of 6-DOF positioning deviations. Through multi-view consistency verification (such as eliminating abnormal registration results), misjudgments from a single view are avoided, making it particularly suitable for scenarios with complex anatomical structures around the target area (such as pelvic and skull base tumors). It supports flexible selection of radiation source positions and allows for customized acquisition schemes based on target area characteristics (such as long strip target areas requiring multi-directional verification), adapting to the precise radiotherapy needs of tumors in multiple locations such as the head and neck, chest and abdomen.

[0143] In one possible implementation, each of the first registration results includes the similarity between the corresponding projected image and the DRR image;

[0144] The multiple similarities are fused to determine the final similarity.

[0145] The patient's positioning deviation is determined based on the final similarity, and parameters for treatment bed correction are output.

[0146] The fusion process for the plurality of similarities includes at least one of averaging, weighted fusion, peak-first fusion, or gradient fusion.

[0147] In the weighted fusion, the weight of each similarity is determined based on at least one of the spatial coverage of the corresponding projected image, noise level, or clinical target area relevance.

[0148] In one possible implementation, the spatial coverage of the image is determined by the distance between the radiation source and the treatment isocenter, as well as the relative relationship between the projection direction and the tomographic direction of the planned CT image. The closer the radiation source is to the isocenter, the higher the spatial coverage of the corresponding projected image and the greater its weight. The more parallel (rather than orthogonal) the projection direction is to the tomographic direction of the planned CT image, the higher the spatial coverage and the greater the weight of the projected image. The relevance of the clinical target area is determined by the principle of priority projection of the target area boundary and coverage of high-risk organs.

[0149] In practical applications, the radiotherapy isocenter is the core reference point for focusing X-rays and planning CT images (such as the tumor center). When the X-ray source moves to a projection position close to the isocenter, the spatial overlap between the anatomical structures (such as tumors and bones) in the projected image and the planned CT image is the highest.

[0150] For example, in a planned CT image, the tumor in a lung cancer patient is located in the middle of the chest cavity (where the isocenter is set). The X-ray source moves along a vertical path. When it reaches the isocenter height, the projected coronal image of the chest clearly shows the positional relationship between the tumor and the left and right hilum and ribs, with almost the same viewpoint as the planned CT image, resulting in high spatial coverage. Conversely, if the X-ray source moves to the top of the path (away from the isocenter, such as above the head), the projected image will look down on the chest cavity, compressing the tumor and deforming the ribs, resulting in a significant difference in spatial relationship from the planned CT image and low spatial coverage.

[0151] The planned CT image is a tomographic image of the patient in a supine position (e.g., a transverse axial view). If the projected image is a coronal / sagittal projection acquired by the X-ray source in a vertical direction, it will form an orthogonal complement to the transverse axial view of the planned CT image, which can verify the left-right / up-down offset of the positioning. If the projection direction is completely parallel to the planned CT image (e.g., the X-ray source moves horizontally to acquire a transverse axial projection), it will be closer to the spatial coverage of the planned CT image and have a higher degree of overlap with the anatomical structures.

[0152] Clinical target relevance describes the ability of projected images to display the target area (tumor) and organs at risk (normal tissue). It can directly determine whether positioning deviations lead to incorrect radiotherapy doses. Clinical target relevance is determined by prioritizing target boundary projection and covering high-risk organs.

[0153] Target boundary projection priority:

[0154] If the projected image happens to pinpoint the critical location between the target area and the organ at risk, this type of projection has extremely high clinical relevance.

[0155] For example, in radiotherapy for nasopharyngeal carcinoma, the target area is close to the brainstem (an organ at risk). When the radiation source is moved to a lateral projection position (e.g., the radiation source is on the left side of the patient, and a sagittal projection is acquired), the projection image can clearly show the lateral boundary between the nasopharyngeal tumor (target area) and the brainstem. Once the positioning is off, the change in the distance between the tumor and the brainstem in the projection directly corresponds to whether the brainstem will be over-irradiated → clinical relevance is maximized.

[0156] Conversely, if the projection only shows the center of the tumor (far from organs at risk), even if the positioning is off, it is difficult to directly determine whether normal tissue is damaged → low clinical relevance.

[0157] High-risk organ coverage:

[0158] During radiotherapy, certain organs are extremely sensitive to radiation (such as the spinal cord, eyeballs, and kidneys); if the projection image can completely cover these high-risk organs and the target area, it will have higher clinical relevance.

[0159] For example, in breast cancer radiotherapy, the target area is in the chest, and the organ at risk is the heart. When the radiation source is moved to a forward and lateral projection position, the projected image can simultaneously show the anterior-posterior positional relationship between the breast tumor (target area) and the heart (organ at risk). → When the position shifts, it can be directly observed whether the tumor has moved or whether the heart is covered by radiation. → This is something that clinicians must pay attention to, as it has a high correlation.

[0160] For example: the outline boundary of the target area (such as a tumor) is identified by the planned CT image. When the overlap length between the target area outline and the planned CT image outline in the projected image is greater than or equal to a preset ratio (e.g., 80%) of the target area perimeter, it is determined to be the target area boundary projection and assigned a first weight (e.g., 1.5, and a normal weight is, for example, 1).

[0161] For example, the location of organs at risk (such as the spinal cord and eyeballs) in the planned CT images is pre-marked. When the minimum distance between the organ at risk and the target area in the projected image is less than or equal to the distance threshold (e.g., ≤5mm clinical high-risk threshold), it is judged as a high-risk coverage projection and assigned a second weight (e.g., 1.3). If the projection simultaneously satisfies the target area boundary + high-risk coverage, it is assigned a third weight (e.g., 1.6).

[0162] The effects of the above technical solution are as follows:

[0163] By averaging and weighted fusion of multiple similarities, spatial information from multi-view projection images can be integrated, avoiding registration errors caused by noise, artifacts, or viewpoint limitations in single projections. For example, the complementary information between orthogonal and parallel projections, combined with the rule that "the closer the X-ray source is to the isocenter, the higher the weight," can prioritize the use of accurate information from high-coverage projections, reducing positioning errors caused by misjudgments from a single viewpoint, and making the 6-DOF deviation calculation closer to the patient's actual position.

[0164] Determining the relevance weight of clinical target volumes based on the principles of prioritizing target boundary projection and covering high-risk organs can significantly enhance attention to the tumor-at-risk organ boundary. For example, in nasopharyngeal carcinoma radiotherapy, a high weighting of lateral projection can directly warn of potential brainstem damage caused by positioning deviations; in breast cancer radiotherapy, a weighting bias towards anterior lateral projection can accurately verify whether the heart has been over-irradiated, thus mechanistically reducing the risk of excessive dose to normal tissues.

[0165] Spatial coverage weighting combines the distance from the isocenter and the parallelism of the projection direction with the planned CT image. This ensures the core position of high-overlap projections near the isocenter and enhances the deviation verification dimension through supplementary information from orthogonal projection. Clinical relevance weighting is standardized through quantitative thresholds (such as 80% overlap of target area contours and ≤5mm of high-risk distance) to avoid subjective judgment errors and make weight allocation more scientific and reproducible.

[0166] Multiple fusion methods (such as peak-priority fusion to remove outliers and gradient fusion to highlight sensitive parameters) can address the characteristics of different radiotherapy sites: for pelvic tumors with complex anatomical structures, multi-view weighted fusion can balance bone interference and target area display; for skull base tumors adjacent to high-risk organs, projection with high clinical relevance weights can prioritize locking key boundaries and ensure that the positioning correction focuses on the deviation direction with the highest clinical risk.

[0167] The relative relationship between the projection direction and the tomographic direction of the planned CT image is incorporated into the weight calculation, making the registration process more consistent with the original imaging logic of the planned CT image—parallel projection ensures the overlap of the basic structure, and orthogonal projection supplements the three-dimensional space verification, reducing the systematic error of cross-modal registration.

[0168] In one possible implementation, determining the patient's positioning deviation based on the final similarity includes:

[0169] By combining the ray source angles corresponding to each projection image, a mapping relationship between the combination of placement parameters and the final similarity is established;

[0170] The optimal combination of placement parameters corresponding to the final similarity in the mapping relationship is searched using a multidimensional optimization algorithm, and this combination is determined as the placement deviation.

[0171] The multidimensional optimization algorithm includes at least one of particle swarm optimization algorithm or simulated annealing algorithm.

[0172] In one possible implementation, before processing the plurality of similarities, a consistency check is performed on the plurality of similarities to remove outliers.

[0173] Combining the X-ray source angles (i.e., projection viewpoints) corresponding to each projection image, the 6-DOF positioning parameter combination (X, Y, Z axis translation and rotation around the three axes) is used as input. By calculating and fusing the similarities between multiple projection images and corresponding DRR images under this parameter combination, the final similarity is obtained, forming a mapping relationship between positioning parameter combination and final similarity (parameter space with multi-angle constraints). Using multi-dimensional optimization algorithms such as particle swarm optimization or simulated annealing, the positioning parameter combination that results in the optimal (e.g., maximum) final similarity is searched in the above mapping relationship and identified as the patient's positioning deviation. Before fusing multiple similarities, outliers (e.g., similarities deviating from the mean by more than a preset threshold) are identified and removed through statistical analysis (e.g., calculating the mean and standard deviation) to ensure the reliability and consistency of the similarities involved in the fusion. Multidimensional optimization algorithms can efficiently handle the coordinated optimization of 6-DOF positioning parameters and solve the complex problems caused by the coupling of translation and rotation parameters (such as rotational deviation may be accompanied by translational deviation in head and neck tumor positioning). At the same time, the algorithm's flexibility can adapt to the parameter accuracy requirements of different target areas (such as intracranial tumors being more sensitive to rotational deviation), and personalized optimization can be achieved by adjusting the search accuracy.

[0174] In one possible implementation, the number of projected images (number of location points) is determined through dynamic adaptation of multi-dimensional clinical and individual characteristics; including:

[0175] A projection quantity decision model is constructed. The inputs of the projection quantity decision model include tumor anatomical location (such as head and neck, body), planned target volume, historical registration error trend, patient physiological movement amplitude and registration pattern (such as breathing, voluntary movement);

[0176] The projection quantity decision model dynamically allocates projection density based on a preset anatomical structure coverage priority (e.g., target area > organs at risk > normal tissue). The result satisfies the following conditions: the minimum projection density required for coverage of key anatomical structures, and the patient's radiation dose is limited to a safe threshold.

[0177] In one possible implementation, the first preset distance is determined in the following manner:

[0178] Based on the number of projection position points output by the projection number decision model, the total journey of the first preset path is divided into intervals that match the number of projection position points in the direction of movement, and the length of each interval is the basic step size.

[0179] The basic step size is adapted and optimized using a dynamic step size adjustment model. The inputs of the dynamic step size adjustment model include:

[0180] The patient's structural-dose characteristics and physiological-motor characteristics; the structural-dose characteristics include the volume and shape complexity of the target area, its spatial proximity to organs at risk, and the radiation sensitivity level of normal tissues outside the target area; the physiological-motor characteristics include respiratory amplitude, voluntary movement frequency, and range.

[0181] The output of the step size dynamic adjustment model is the specific step size value of each interval on the first preset path, wherein: for the interval corresponding to the target area, the model outputs the reduction magnitude according to the structure-dose characteristics (e.g., the smaller the target area volume, the more complex the shape, or the closer it is to the organ at risk, the greater the reduction magnitude).

[0182] Based on the structural-dose characteristics, physiological motion characteristics, and corresponding optimal step size allocation cases of a large number of patients, a dynamic step size adjustment model is constructed using machine learning and other methods, enabling it to generalize and adapt to different patient characteristics. For the current patient, individualized structural-dose characteristics (such as self-target volume, normal tissue sensitivity, etc.) and real-time physiological motion characteristics are extracted, input into the pre-trained model, and the output is a step size adjustment scheme specific to the patient.

[0183] The step size dynamic adjustment model and the projection quantity decision model are related but independent models. The former is based on the total number of position points output by the latter to achieve fine allocation of step size in each interval. The first preset distance formed in the end satisfies the minimum projection density of key anatomical structures, and the patient's radiation dose is limited within a safe threshold, while balancing registration accuracy and acquisition efficiency.

[0184] The effects of the above technical solution are as follows:

[0185] By integrating individualized structural-dose characteristics and physiological motion characteristics of patients through a step-size dynamic adjustment model, the step-size allocation of the radiation source movement is highly adapted to the specific situation of the patient. This ensures high-resolution projection coverage of key structures such as the target area while avoiding redundant acquisition of non-critical areas, thereby improving the accuracy of image guidance.

[0186] The step size is dynamically adjusted based on the radiation sensitivity level of normal tissues outside the target area (maintaining a smaller step size increment when sensitivity is high and increasing the step size when sensitivity is low). This ensures that the overall radiation dose to the patient is strictly controlled within a safe threshold while meeting image quality requirements, reducing the risk of damage to normal tissues. The step size is also adjusted in real time based on the patient's physiological movement characteristics (such as respiratory amplitude and range of voluntary movement). When the movement amplitude is large, the step size is reduced to ensure registration accuracy; when the movement amplitude is small, the step size is increased to shorten acquisition time. This achieves an optimal balance between accuracy and efficiency, improving the smoothness of the treatment process.

[0187] The step length dynamic adjustment model, trained based on a large amount of patient data, has generalization and adaptation capabilities, covering patients with different anatomical features and movement states. At the same time, it outputs a personalized step length plan for the current patient, taking into account both group patterns and individual differences, thereby improving the clinical applicability of the device.

[0188] The interconnected yet independent division of labor (the former determines the total amount, while the latter provides fine-grained allocation) ensures that the overall layout of the projection points meets the minimum density requirements for covering key structures, while also achieving optimal resource allocation through step size optimization, thereby enhancing the intelligence and efficiency of the image guidance device.

[0189] See attached document Figure 3 This invention provides an image-guided method for radiotherapy equipment, the method comprising:

[0190] A radiation source positioned on one side of the center of the treatment room is controlled to move along a first preset path, emitting radiation during the movement, and the radiation passes through the patient;

[0191] The detector, which is located on the other side of the center of the treatment room and is distributed relative to the radiation source along the center, moves along a second preset path to collect the radiation after passing through the patient and convert it into a corresponding projection image; wherein, both the first preset path and the second preset path are straight lines.

[0192] The projected image is processed and registered with the planned CT image to calculate the positioning deviation;

[0193] Both the first preset path and the second preset path are straight lines.

[0194] In one possible implementation, the movement of the X-ray source and detector, as well as the angular rotation of the X-ray source, are driven by a motion control module.

[0195] In one possible implementation, the first preset path and the second preset path are parallel to each other.

[0196] In one possible implementation, both the first and second preset paths are vertical straight lines along the direction of gravity; the detector moves in the opposite direction to the radiation source.

[0197] In one possible implementation, the projected image is obtained in the following ways:

[0198] The X-ray source is moved along the first preset path until the end of the journey, and at the preset position on the moving trajectory, the patient's projected image is acquired by the detector.

[0199] When the radiation source moves along the first preset path, the central axis of the radiation source is always aligned with the center of the treatment room. When the radiation source moves a first preset distance to the first preset position, the detector is moved in the opposite direction along the second preset path by a second preset distance, either synchronously or asynchronously, so that the radiation beam and the receiving surface of the detector are aligned together to collect the patient's projected image.

[0200] In one possible implementation, the total travel of the first preset path is determined based on the distribution range of the patient's target area and key anatomical structures, ensuring that the movement of the radiation source from the starting position to the ending position along the direction of movement enables the radiation beam to completely cover the target area; the position of the end of the radiation source travel is set collaboratively by radiotherapy planning parameters, patient and target area characteristics, and equipment physical constraints.

[0201] In one possible implementation, the registration of the projected image with the planned CT image is achieved by performing a first registration mode, including:

[0202] The X-ray source is moved to multiple locations along the entire first preset path to acquire multiple projection images;

[0203] CBCT images are generated by 3D reconstruction of multiple projection images;

[0204] The CBCT images are registered with the planned CT images, the positioning deviation is calculated, and parameters for treatment bed correction are output.

[0205] In one possible implementation, the registration of the projected image with the planned CT image is achieved by performing a second registration mode, including:

[0206] Projected images are acquired at any position along the trajectory of the moving X-ray source;

[0207] The projected image is registered with the DRR image generated from the planned CT image to obtain the first registration result;

[0208] Based on the first registration result, calculate the positioning deviation and output the parameters for correction of the treatment bed.

[0209] In one possible implementation, the first registration result includes the similarity between the projected image and the DRR image (such as mutual information, normalized cross-correlation coefficient, etc.);

[0210] The patient's positioning deviation is determined based on the similarity, and parameters for correction of the treatment bed are output; the positioning deviation includes 6 degrees of freedom deviation (including translation of the X, Y, and Z axes and rotation around the three axes).

[0211] In one possible implementation, determining the patient's positioning deviation based on the similarity includes:

[0212] Establish a mapping relationship between the combination of placement parameters and the similarity, wherein the combination of placement parameters includes translation parameters and / or rotation parameters;

[0213] Search for the optimal combination of placement parameters in the mapping relationship and determine it as the placement deviation.

[0214] In this process, a mapping relationship is established by iteratively adjusting the combination of placement parameters (translation and rotation parameters) and calculating the corresponding similarity.

[0215] In one possible implementation, the registration of the projected image with the planned CT image is achieved by performing a second registration mode, including:

[0216] Projected images are acquired at at least two locations along the trajectory of the radiation source.

[0217] Obtain DRR images corresponding to each of the projected images generated from the planned CT images;

[0218] Each of the projected images is registered with its corresponding DRR image to obtain multiple first registration results.

[0219] Based on multiple first registration results, the positioning deviation is calculated and parameters for treatment bed correction are output.

[0220] In one possible implementation, each of the first registration results includes the similarity between the corresponding projected image and the DRR image;

[0221] The multiple similarities are fused to determine the final similarity.

[0222] The patient's positioning deviation is determined based on the final similarity, and parameters for treatment bed correction are output.

[0223] The fusion process for the plurality of similarities includes at least one of averaging, weighted fusion, peak-first fusion, or gradient fusion.

[0224] In the weighted fusion, the weight of each similarity is determined based on at least one of the spatial coverage of the corresponding projected image, noise level, or clinical target area relevance.

[0225] In one possible implementation, the spatial coverage of the image is determined by the distance between the radiation source and the treatment isocenter, as well as the relative relationship between the projection direction and the tomographic direction of the planned CT image. The closer the radiation source is to the isocenter, the higher the spatial coverage of the corresponding projected image and the greater its weight. The more parallel (rather than orthogonal) the projection direction is to the tomographic direction of the planned CT image, the higher the spatial coverage and the greater the weight of the projected image. The relevance of the clinical target area is determined by the principle of priority projection of the target area boundary and coverage of high-risk organs.

[0226] In one possible implementation, each of the first registration results includes the similarity between the corresponding projected image and the DRR image;

[0227] The multiple similarities are fused to determine the final similarity.

[0228] The patient's positioning deviation is determined based on the final similarity, and parameters for treatment bed correction are output.

[0229] The fusion process for the plurality of similarities includes at least one of averaging, weighted fusion, peak-first fusion, or gradient fusion.

[0230] In the weighted fusion, the weight of each similarity is determined based on at least one of the spatial coverage of the corresponding projected image, noise level, or clinical target area relevance.

[0231] In one possible implementation, the spatial coverage of the image is determined by the distance between the radiation source and the treatment isocenter, as well as the relative relationship between the projection direction and the tomographic direction of the planned CT image. The closer the radiation source is to the isocenter, the higher the spatial coverage of the corresponding projected image and the greater its weight. The more parallel (rather than orthogonal) the projection direction is to the tomographic direction of the planned CT image, the higher the spatial coverage and the greater the weight of the projected image. The relevance of the clinical target area is determined by the principle of priority projection of the target area boundary and coverage of high-risk organs.

[0232] In one possible implementation, the number of projected images (number of location points) is determined through dynamic adaptation of multi-dimensional clinical and individual characteristics; including:

[0233] A projection quantity decision model is constructed. The inputs of the projection quantity decision model include tumor anatomical location (such as head and neck, body), planned target volume, historical registration error trend, patient physiological movement amplitude and registration pattern (such as breathing, voluntary movement);

[0234] The projection quantity decision model dynamically allocates projection density based on a preset anatomical structure coverage priority (e.g., target area > organs at risk > normal tissue). The result satisfies the following conditions: the minimum projection density required for coverage of key anatomical structures, and the patient's radiation dose is limited to a safe threshold.

[0235] In one possible implementation, the first preset distance is determined in the following manner:

[0236] Based on the number of projection position points output by the projection number decision model, the total journey of the first preset path is divided into intervals that match the number of projection position points in the direction of movement, and the length of each interval is the basic step size.

[0237] The basic step size is adapted and optimized using a dynamic step size adjustment model. The inputs of the dynamic step size adjustment model include:

[0238] The patient's structural-dose characteristics and physiological-motor characteristics; the structural-dose characteristics include the volume and shape complexity of the target area, its spatial proximity to organs at risk, and the radiation sensitivity level of normal tissues outside the target area; the physiological-motor characteristics include respiratory amplitude, voluntary movement frequency, and range.

[0239] The output of the step size dynamic adjustment model is the specific step size value of each interval on the first preset path.

[0240] The working principle and effect of the above technical solution are the same as those in the embodiments of the present invention, and will not be repeated here.

[0241] This invention also provides a radiotherapy system, including an image guidance device for radiotherapy equipment as described in any of the embodiments of this invention. The radiotherapy system includes a rotating gantry 605 installed in a treatment room 612, a particle accelerator 604 installed on the rotating gantry 605 for providing a particle beam, a treatment bed 606 for supporting a patient 607 and moving the patient to an isocentric position, and a treatment head 621 for treating the patient's treatment area. The treatment head 621 rotates along a rotation direction 615 on a movement path or track 611, and a particle beam is emitted from the end of the treatment head to treat the patient. The image guidance device for radiotherapy equipment is installed on a pair of spaced-apart vertical walls 613 in the treatment room 612, and the particle accelerator may be a proton accelerator.

[0242] This invention also provides an electronic device, which includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the steps of any of the methods or the functions of the devices described in this invention.

[0243] This invention also provides a computer-readable storage medium for storing a computer program. When the computer program is executed, it implements the steps of the method in this invention. The specific implementation method is consistent with the implementation method and the technical effect achieved in the above method embodiments, and some contents will not be repeated.

[0244] In this invention, a readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. The program product can take the form of any combination of one or more readable media. A readable medium can be a readable signal medium or a readable storage medium. A readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of readable storage media (a non-exhaustive list) include: an electrical connection having one or more wires, a portable disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0245] Computer-readable storage media may include data signals propagated in baseband or as part of a carrier wave, carrying readable program code. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. The readable storage medium may also be any readable medium capable of sending, propagating, or transmitting a program for use by or in conjunction with an instruction execution system, apparatus, or device. The program code contained on the readable storage medium may be transmitted using any suitable medium, including but not limited to wireless, wired, optical fiber, RF, or any suitable combination thereof. Program code for performing operations of the present invention may be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java and C++, as well as conventional procedural programming languages ​​such as C or similar programming languages. The program code may be executed entirely on a user computing device, partially on an associated device, as a standalone software package, partially on a user computing device and partially on a remote computing device, or entirely on a remote computing device or server. In cases involving remote computing devices, the remote computing devices can be connected to user computing devices via any type of network, including local area networks (LANs) or wide area networks (WANs), or they can be connected to external computing devices (e.g., via the Internet using an Internet service provider).

[0246] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the invention without departing from the principles and spirit of the invention, and all such changes should fall within the protection scope of the claims of the present invention.

Claims

1. An image guidance device for radiotherapy equipment, characterized in that, The device includes: A radiation generating module, equipped with a radiation source, is positioned on one side of the center of a treatment room, etc.; the radiation source is used to move along a first preset path; the radiation source is used to emit radiation, and the radiation passes through the patient; The detection and acquisition module is equipped with a detector, which is located on the other side of the center of the treatment room and is distributed relative to the radiation source along the center; the detector is used to move along a second preset path to collect the radiation after passing through the patient and convert it into a corresponding projection image. The registration module is used to register the projected image with the planned CT image by executing a first registration mode or a second registration mode to calculate the positioning deviation. The first and second preset paths are both straight lines and parallel to each other. The first and second preset paths are not on the movement path of the treatment head and are not parallel to the movement path of the treatment head. The detector moves in the opposite direction to the radiation source. When the radiation source moves along the first preset path, the central axis of the radiation source is always aligned with the center of the treatment room. The central axis of the detector and the central axis of the radiation source both pass through the center of the treatment room. The detector and the radiation source move before the treatment head moves around the patient to perform treatment. The first registration mode includes: The X-ray source is moved to multiple locations along the entire first preset path to acquire multiple projection images; CBCT images are generated by 3D reconstruction of multiple projection images; The CBCT images are registered with the planned CT images, the positioning deviation is calculated, and parameters for treatment bed correction are output. The second registration mode includes: Projected images are acquired at at least two locations along the trajectory of the radiation source. Obtain DRR images corresponding to each of the projected images generated from the planned CT images; Each of the projected images is registered with its corresponding DRR image to obtain multiple first registration results. The similarity in each of the first registration results is weighted and fused to determine the final similarity; based on the final similarity and combined with the ray source angle corresponding to each projection image, a multidimensional optimization algorithm is used to search for the optimal combination of positioning parameters, calculate the positioning deviation, and output the parameters for correction of the treatment bed. In the weighted fusion process, the weight of each similarity is determined based on the spatial coverage of the corresponding projected image and the clinical target area correlation; the spatial coverage is determined by the distance between the radiation source and the center of the treatment room, and the clinical target area correlation is determined by the principle of priority projection of target area boundary and coverage of high-risk organs.

2. The image guidance device for radiotherapy equipment according to claim 1, characterized in that, Both the first preset path and the second preset path are vertical straight lines along the direction of gravity.

3. The image guidance device for radiotherapy equipment according to claim 1, characterized in that, The device acquires the projected image in the following ways: The X-ray source is moved along the first preset path until the end of the journey, and at the preset position on the moving trajectory, the patient's projected image is acquired by the detector. When the radiation source moves along the first preset path, the central axis of the radiation source is always aligned with the center of the treatment room. When the radiation source moves a first preset distance to its preset position, the detector is moved in the opposite direction along the second preset path by a second preset distance so that the radiation beam and the receiving surface of the detector are aligned so as to collect the patient's projected image.

4. The image guidance device for radiotherapy equipment according to claim 1, characterized in that, The second registration mode also includes: Projected images are acquired at any position along the trajectory of the moving X-ray source; The projected image is registered with the DRR image generated from the planned CT image to obtain the first registration result; Based on the first registration result, calculate the positioning deviation and output the parameters for correction of the treatment bed.

5. An image-guided method for radiotherapy equipment, characterized in that, The method includes: A radiation source positioned on one side of the center of the treatment room is controlled to move along a first preset path, emitting radiation during the movement, and the radiation passes through the patient; The detector, which is located on the other side of the center of the treatment room and is distributed relative to the radiation source along the center, moves along a second preset path to collect the radiation after passing through the patient and convert it into a corresponding projection image; wherein, both the first preset path and the second preset path are straight lines. The projected image is processed and registered with the planned CT image to calculate the positioning deviation; Wherein, both the first preset path and the second preset path are straight lines; When the radiation source moves along the first preset path, the central axis of the radiation source is always aligned with the center of the treatment room, and both the central axis of the detector and the central axis of the radiation source pass through the center of the treatment room. The method includes: The X-ray source is moved to multiple locations along the entire first preset path to acquire multiple projection images; CBCT images are generated by 3D reconstruction of multiple projection images; The CBCT image is registered with the planning CT image, the positioning deviation is calculated and the parameters for treatment bed correction are output, thereby executing the first registration mode and realizing the registration of the projected image with the planning CT image; The method further includes: Projected images are acquired at at least two locations along the trajectory of the radiation source. Obtain DRR images corresponding to each of the projected images generated from the planned CT images; Each of the projected images is registered with its corresponding DRR image to obtain multiple first registration results, thereby executing a second registration mode to achieve registration between the projected images and the planned CT images. The similarity in each of the first registration results is weighted and fused to determine the final similarity; based on the final similarity and combined with the ray source angle corresponding to each projection image, a multidimensional optimization algorithm is used to search for the optimal combination of positioning parameters, calculate the positioning deviation, and output the parameters for correction of the treatment bed. In the weighted fusion process, the weight of each similarity is determined based on the spatial coverage of the corresponding projected image and the clinical target area correlation; the spatial coverage is determined by the distance between the radiation source and the center of the treatment room, and the clinical target area correlation is determined by the principle of priority projection of target area boundary and coverage of high-risk organs.

6. The image-guided method for radiotherapy equipment according to claim 5, characterized in that, Both the first and second preset paths are vertical straight lines along the direction of gravity; the detector moves in the opposite direction to the radiation source.

7. The image-guided method for radiotherapy equipment according to claim 5, characterized in that, Projected images can be obtained in the following ways: The X-ray source is moved along the first preset path until the end of the journey, and at the preset position on the moving trajectory, the patient's projected image is acquired by the detector. When the radiation source moves a first preset distance to its preset position, the detector moves in the opposite direction along a second preset path a second preset distance so that the radiation beam and the detector receiving surface are aligned so as to acquire the patient's projected image.

8. The image-guided method for radiotherapy equipment according to claim 5, characterized in that, The method includes: Projected images are acquired at any position along the trajectory of the moving X-ray source; The projected image is registered with the DRR image generated from the planned CT image to obtain the first registration result; Based on the first registration result, the positioning deviation is calculated and parameters for treatment bed correction are output, thereby executing the second registration mode to achieve registration of the projected image with the planned CT image.

9. A radiotherapy system, characterized in that, include: The image guidance device for radiotherapy equipment according to any one of claims 1-4.

10. An electronic device, characterized in that, The electronic device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to perform the functions of the device according to any one of claims 1-4 or the steps of the method according to any one of claims 5-8.

11. A computer-readable storage medium, characterized in that, The storage medium stores computer instructions, and when the computer reads the computer instructions, the computer executes the steps of the method as described in any one of claims 5-8.

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