A radiotherapy target positioning method based on degradable visualized ceramic marker

Abstract

This invention discloses a method for radiotherapy target localization based on biodegradable radiopaque ceramic markers. The method involves customizing and standardizing biodegradable radiopaque ceramic markers to match the radiotherapy cycle, based on pre-defined tumor lesion parameters and full-cycle radiotherapy parameters. Target area image data of the implanted non-coplanar markers are acquired, and coordinate system registration, precise target delineation, and radiotherapy planning parameters are determined based on CT thin-slice images. Before radiotherapy, the markers are used to verify their position, and positioning correction parameters are output for radiotherapy equipment calibration. After radiotherapy, the degradation of the markers is monitored based on follow-up images. This invention achieves precise radiotherapy target localization, uses markers without artifact imaging, has a degradation cycle precisely matched to the radiotherapy cycle, is completely degradable without the need for secondary surgery, and exhibits excellent biocompatibility.

Description

Technical Field

[0001] This invention relates to the field of tumor radiotherapy target localization technology, and in particular to a radiotherapy target localization method based on biodegradable radioactive ceramic markers. Background Technology

[0002] Radiotherapy target localization data processing technology is a core supporting technology for radiotherapy of malignant tumors. More than half of cancer patients in clinical practice require radiotherapy during treatment, and accurate target localization is a crucial prerequisite for ensuring the efficacy of radiotherapy and reducing radiation damage to normal tissues. Precise delineation of the tumor target area, accurate formulation of radiotherapy planning parameters, and equipment execution control all rely on stable and clear localization markers as spatial reference benchmarks. The imaging performance, positional stability, and biocompatibility of these markers directly determine the accuracy of radiotherapy target localization and the overall safety of treatment. Currently, commonly used localization markers are mainly made of metal. While these markers have excellent imaging performance, they produce severe metal artifacts in CT images, interfering with the accurate delineation of the tumor target area and surrounding organs at risk. Furthermore, metal markers are non-degradable in the body, requiring a second surgery for removal after radiotherapy. This not only increases the patient's surgical risks, medical costs, and physical and mental suffering, but also may cause chronic inflammatory reactions in local tissues if left in the body long-term. Another type of polymer marker, although it has good biocompatibility, has poor imaging performance, insufficient contrast in CT images, and is prone to positioning deviations. It cannot meet the clinical needs of high-precision radiotherapy, and the degradation rate of the material in vivo is uncontrollable, making it impossible to achieve precise matching with the pre-set radiotherapy cycle.

[0003] While traditional ceramic markers possess certain imaging properties and biocompatibility, most are non-degradable materials, requiring secondary surgery for removal and thus failing to meet the clinical needs of short-term radiotherapy. Existing biodegradable marker technologies largely fail to simultaneously address the three core requirements of high-contrast imaging, controllable degradation, and excellent biocompatibility. Doping with imaging elements often alters the material's physicochemical properties, affecting its degradation performance, while controlling the degradation rate can easily lead to a decrease in imaging effectiveness, making it impossible to achieve synergistic optimization of imaging and degradation performance. Furthermore, existing radiotherapy target localization methods mostly focus only on extracting basic marker localization parameters, lacking a precise matching mechanism between marker degradation cycles and radiotherapy cycles. They also lack a standardized localization data processing system covering the entire process from marker parameter customization, localization image data processing, precise target delineation, positioning correction parameter calculation to degradation status monitoring. Target positioning deviations during radiotherapy cannot be accurately quantified and corrected with equipment parameters, easily leading to discrepancies between radiotherapy plan parameters and actual execution. This not only affects the final efficacy of radiotherapy but may even cause radiation damage to surrounding normal tissues.

[0004] With the rapid development of precision radiotherapy technology, the application of high-precision radiotherapy techniques such as stereotactic radiotherapy and intensity-modulated radiotherapy (IMRT) in clinical practice continues to expand. These techniques place higher demands on the accuracy of target localization, the safety of radiomarks, and their clinical suitability. Currently, there is an urgent clinical need for a localization marker that can simultaneously achieve high-contrast, artifact-free imaging, precise matching of degradation and radiotherapy cycles, no need for secondary surgical removal, and excellent biocompatibility, along with a standardized, end-to-end radiotherapy target localization method. This would address many shortcomings in existing technologies, improve the accuracy of radiotherapy target localization and the safety of radiotherapy planning, and ultimately enhance the patient's treatment experience and clinical benefits. Summary of the Invention

[0005] This invention proposes a method for radiotherapy target localization based on biodegradable radiopaque ceramic markers to solve the problems mentioned in the prior art.

[0006] To achieve the above objectives, the present invention employs the following technical solution: a method for radiotherapy target localization based on biodegradable radiopaque ceramic markers. Based on the preset tumor lesion parameters and the full cycle parameters of radiotherapy, the parameters of the biodegradable radioactive ceramic marker are customized, and the matrix material ratio, doping ratio of radioactive elements, morphology and size, internal porosity and target degradation cycle of the marker are determined, so that the in vivo degradation cycle of the marker matches the preset full cycle of radiotherapy. The markers were prepared by doping high atomic number developing elements into a biodegradable ceramic matrix material. The ceramic markers were prepared through a standardized process involving powder mixing, pre-pressing, high-temperature sintering, surface micropore treatment, sterilization and packaging. Acquire thin-layer image data of the target area where the ceramic markers are implanted, wherein the ceramic markers are at least three and are distributed in a non-coplanar spatial distribution around the tumor lesion in the target area reference region; Based on the artifact-free imaging characteristics of markers in the thin-layer imaging data, the precise registration of the image coordinate system and the radiotherapy coordinate system is completed. Combined with the plain and enhanced imaging information of the tumor lesion, the precise layer delineation of the radiotherapy target area and the scope of surrounding organs at risk are completed. Based on the spatial relationship between the delineated target area and the markers, radiotherapy planning parameters are formulated to determine the incident angle of the radiotherapy rays, the dose of each irradiation, the total number of irradiation sessions, and the dose distribution scheme of the target area, so that the high-dose area of ​​radiotherapy completely covers the target area while controlling the radiation dose to organs at risk within safe limits. Acquire cone-beam CT image data before radiotherapy, and calculate target placement correction parameters based on the deviation between the actual spatial position of the markers in the images and the reference position in the radiotherapy plan, for six-dimensional position correction of the radiotherapy equipment; Acquire follow-up imaging data after the completion of the entire radiotherapy cycle, extract and output data on the degradation of markers in vivo and changes in lesions in the tumor target area.

[0007] Furthermore, it also includes a precise matching and optimization step for the marker degradation cycle and the radiotherapy cycle. In the marker parameter customization stage, based on the preset radiotherapy fractionation plan, the metabolic characteristics of the lesion tissue, and the physiological environmental characteristics of the implantation area, a calculation formula for regulating the marker degradation cycle is introduced: ; in The actual complete degradation cycle of the marker in human tissues, This is the preset total duration of the entire radiotherapy cycle. The weighting coefficient for the effect of marker porosity on degradation rate. The internal interconnected porosity of the marker. The weighting coefficient for the effect of ceramic matrix grain size on degradation rate. The average grain size of the marker ceramic matrix, The weighting coefficient represents the effect of the doping ratio of developing elements on the degradation rate. This represents the mass doping percentage of the developing element in the ceramic matrix.

[0008] Furthermore, it also includes a multi-dimensional optimization layout step for marker implantation sites. Based on the three-dimensional spatial morphology data of the tumor lesion, the distribution location data of surrounding organs at risk, and the preset incident path of the radiotherapy rays, the optimized design of the marker implantation sites is completed, and the implantation sites with non-coplanar spatial distribution are determined so that the spatial straight-line distance between each marker is kept within the preset range of 2cm to 5cm. At the same time, the main incident path of the radiotherapy rays and the avoidance scheme of surrounding important organs at risk are planned. After the implantation site design is completed, the corresponding puncture implantation path planning parameters are output.

[0009] Furthermore, it also includes a precise quantification step for radiotherapy positioning deviation. Based on the actual spatial position of markers in the acquired images and the reference position of markers in the radiotherapy plan, a quantitative calculation formula for comprehensive target positioning deviation is introduced: ; in This represents the overall positioning deviation value of the patient's tumor target area. The linear positional deviation of the marker in the left-right direction. The linear positional deviation of the marker in the front-to-back direction. The linear positional deviation of the marker in the head-to-feet direction. The comprehensive rotational deviation angle of the marker in three-dimensional space. The equivalent sphere diameter of the tumor target area.

[0010] Furthermore, in the preparation step of the biodegradable developing ceramic marker, the biodegradable ceramic matrix material adopts one or more composites of β-tricalcium phosphate, calcium silicate, and magnesium-based bioceramics, and the developing element doped adopts one or more high atomic number elements of barium, bismuth, strontium, and tantalum. The mass doping ratio of the developing element is controlled between 5% and 20%. The morphology of the marker is set as cylindrical, spherical, or sheet-like, the diameter of the marker is controlled between 1 mm and 3 mm, the length is controlled between 3 mm and 10 mm, and the surface of the marker is provided with a connected microporous structure with the pore size controlled between 50 μm and 200 μm.

[0011] Furthermore, in the entire process of preparing the biodegradable and developable ceramic marker, the mixing step uses a wet ball milling process to uniformly mix the ceramic matrix powder and the developing element powder. Anhydrous ethanol is used as the ball milling medium. After ball milling, spray drying is performed to obtain a mixed powder with excellent flowability. The molding step uses dry injection molding or photopolymerization 3D printing to prepare the marker preform. The sintering temperature in the high-temperature sintering step is controlled between 1000℃ and 1300℃. During the sintering process, the heating rate and holding time are precisely controlled to regulate the grain size and internal porosity of the marker ceramic matrix. The surface treatment step uses sandblasting or chemical etching to adjust the surface microporous structure and roughness. The sterilization step uses ethylene oxide sterilization or high-temperature and high-pressure steam sterilization. After sterilization, the product is sealed and packaged in a sterile environment.

[0012] Furthermore, the thin-layer image data of the target area is image data acquired by a large-aperture CT device or ultrasound device, including markers implanted with a coaxial puncture needle. The puncture and implantation path of the markers is a pre-planned path that avoids major blood vessels, nerve bundles and important functional organs. The image data includes thin-layer scan data in three dimensions: axial, coronal and sagittal.

[0013] Furthermore, in the radiotherapy target delineation and treatment planning steps, based on the high-contrast imaging characteristics of markers without metal artifacts in CT images, rigid registration of the image coordinate system and the radiotherapy coordinate system is completed. Combining the plain CT and enhanced CT image information of the tumor lesion, the gross tumor target area, clinical target area, and planned target area are accurately delineated layer by layer. At the same time, the extent of organs at risk around the tumor and the maximum radiation dose limit are defined. Based on the delineated target area, intensity-modulated radiotherapy planning parameters or stereotactic radiotherapy planning parameters are formulated.

[0014] Furthermore, in the positioning verification and correction step, the cone-beam CT image data is real-time image data acquired by an airborne cone-beam CT scanner. The three-dimensional spatial position of the marker is automatically located through an image recognition algorithm and automatically compared with the reference position of the marker in the radiotherapy planning system. The full-dimensional positioning deviation of the target area is calculated. When the overall positioning deviation exceeds a preset threshold of 0.3mm, the position correction parameters of the six-dimensional treatment bed are generated for automatic position correction of the treatment bed. After the correction is completed, the deviation verification result is output, and the position information of the marker and the irradiation parameters are recorded at the same time.

[0015] Furthermore, the follow-up imaging data consists of CT images collected at 1 month, 3 months, 6 months, and 12 months after the completion of the entire radiotherapy cycle. Based on the follow-up imaging data, data on the degradation of the marker in vivo, changes in lesions in the tumor target area, and tissue response in the marker implantation area are extracted and output.

[0016] Compared with existing technologies, the beneficial effects of this invention are: The radiotherapy target localization method based on biodegradable radioactive ceramic markers of the present invention achieves precise matching between the degradation cycle of the markers and the preset full cycle of radiotherapy through customized design of the biodegradable radioactive ceramic markers. It can maintain a stable structural morphology and radioactive properties throughout the entire radiotherapy cycle. After radiotherapy, it can be gradually and completely degraded in the body without the need for secondary surgery to remove it, which greatly reduces the patient's treatment pain, surgical risks and additional medical costs. At the same time, it avoids the chronic tissue reactions caused by long-term retention of the markers in the body and improves the biosafety of clinical applications.

[0017] The biodegradable radiopaque ceramic marker used in this invention can achieve high-contrast, artifact-free imaging in CT images, effectively solving the artifact interference problem of traditional metal markers. It provides a clear imaging benchmark for the precise registration of the image coordinate system and the radiotherapy coordinate system, and for the precise delineation of the tumor target area, greatly improving the accuracy of target area delineation and radiotherapy planning parameters, and laying a solid foundation for the precise execution of radiotherapy planned doses.

[0018] This invention establishes a standardized radiotherapy target positioning data processing system covering the entire process, from customized marker preparation, implantation site planning parameter output, precise target delineation, precise quantification of positioning deviation and correction parameter output to degradation state data monitoring. Through the non-coplanar spatial layout design of the markers, it achieves full-dimensional precise quantification of linear and rotational deviations during radiotherapy positioning, significantly improving the overlap of target positions during radiotherapy, reducing the risk of target omission and excessive irradiation of normal tissues, and improving the efficacy and safety of radiotherapy.

[0019] The biodegradable radiopaque ceramic markers used in this invention have excellent biocompatibility. The degradation products are inorganic ions that are harmless to the human body and can be absorbed by human tissues or excreted through normal metabolic pathways. They do not produce toxic or harmful substances in the body. At the same time, the microporous structure on the surface of the markers can promote the ingrowth of surrounding human tissues after implantation, effectively reducing the risk of marker displacement and detachment throughout the entire radiotherapy cycle and ensuring the stability of the positioning reference throughout the entire radiotherapy cycle.

[0020] The positioning method of this invention has a standardized and controllable operation process, and can be adapted to routine clinical image-guided puncture equipment, radiotherapy equipment and clinical workflows. It is easy to promote and apply in the radiotherapy departments of medical institutions at all levels. It can meet the positioning needs of tumor patients with different pathological types, different lesion sites and different radiotherapy plans. It has excellent clinical adaptability and application prospects, and can effectively promote the standardized clinical application and development of precision radiotherapy technology. Attached Figure Description

[0021] Figure 1 This is a schematic block diagram of a radiotherapy target localization method based on biodegradable radiopaque ceramic markers proposed in this invention; Figure 2 A logic diagram for precisely matching the degradation cycle of markers with the radiotherapy cycle; Figure 3 A flowchart of the standardized preparation process for biodegradable and developable ceramic markers; Figure 4 A state machine diagram for multi-dimensional optimization of marker layout and precise implantation; Figure 5 This is a chart for quantifying and closed-loop corrective control of six-dimensional positioning deviation in radiotherapy. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0024] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly; for example, they may refer to a fixed connection, a detachable connection, or an integral connection; they may refer to a mechanical connection or an electrical connection; they may refer to a direct connection or an indirect connection through an intermediate medium; and they may refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. The invention will now be described in further detail with reference to the accompanying drawings.

[0025] Reference Figures 1 to 5 A method for radiotherapy target localization based on biodegradable radioactive ceramic markers: Based on preset tumor lesion parameters and full-cycle radiotherapy parameters, the parameters of biodegradable radioactive ceramic markers are customized, and the matrix material ratio, doping ratio of radioactive elements, morphology and size, internal porosity and target degradation cycle of the markers are determined, so that the in vivo degradation cycle of the markers is completely matched with the preset full-cycle radiotherapy. The markers were prepared by doping high atomic number developing elements into a biodegradable ceramic matrix material. The entire process, including powder mixing, pre-pressing, high-temperature sintering, surface micropore treatment, sterilization and packaging, was standardized to prepare ceramic markers with high contrast developing performance, excellent biocompatibility and controllable degradation performance. Acquire multi-dimensional image data of the target area where the biodegradable radiopaque ceramic markers are implanted. The markers are at least three markers distributed in a non-coplanar spatial distribution around the tumor lesion in the target reference area. The image data is used to confirm that the markers have not shifted, fallen off, or caused any puncture-related complications. Acquire thin-slice image data of the entire target area from large-aperture CT, and complete the precise registration of the image coordinate system and the radiotherapy coordinate system based on the artifact-free imaging characteristics of the markers. Combine the plain and enhanced image information of the tumor lesion to complete the precise layer delineation of the radiotherapy target area and the scope of surrounding organs at risk. Based on the spatial relationship between the delineated target area and the markers, radiotherapy planning parameters are formulated to determine the incident angle of the radiotherapy rays, the dose of each irradiation, the total number of irradiation sessions, and the dose distribution scheme of the target area, so that the high-dose area of ​​radiotherapy completely covers the target area while controlling the radiation dose to organs at risk within safe limits. Acquire cone-beam CT image data before radiotherapy, and calculate target placement correction parameters based on the deviation between the actual spatial position of the markers in the images and the reference position in the radiotherapy plan, for six-dimensional position correction of the radiotherapy equipment; Acquire follow-up imaging data after the completion of the entire radiotherapy cycle, extract and output data on the degradation of markers in vivo and changes in lesions in the tumor target area. The markers can be gradually and completely degraded in vivo without the need for a second surgery to remove them.

[0026] This invention also includes a precise matching and optimization step for the marker degradation cycle and the radiotherapy cycle. In the marker parameter customization stage, based on the preset radiotherapy fractionation scheme, lesion tissue metabolic characteristic parameters, and physiological environmental characteristic parameters of the implantation area, a calculation formula for regulating the marker degradation cycle is introduced: ; in The actual complete degradation cycle of the marker in human tissues, This is the preset total duration of the entire radiotherapy cycle. The weighting coefficient for the effect of marker porosity on degradation rate. The internal interconnected porosity of the marker. The weighting coefficient for the effect of ceramic matrix grain size on degradation rate. The average grain size of the marker ceramic matrix, The weighting coefficient represents the effect of the doping ratio of developing elements on the degradation rate. By adjusting the mass doping ratio of imaging elements in the ceramic matrix, the degradation cycle of the marker can be made to completely cover the entire radiotherapy cycle through multi-parameter coordinated adjustment. At the same time, it can be completely degraded within a preset time after radiotherapy, reducing chronic tissue reactions caused by long-term retention of the marker in the body. Furthermore, it eliminates the need for a second surgery to remove the marker, reducing the patient's treatment pain, surgical risks, and additional medical costs.

[0027] This invention also includes a multi-dimensional optimization layout step for marker implantation sites. In the marker parameter customization stage, based on the three-dimensional spatial morphology data of the tumor lesion, the distribution location data of surrounding organs at risk, and the preset incident path of the radiotherapy rays, the optimized design of the marker implantation sites is completed, and the implantation sites with non-coplanar spatial distribution are determined so that the spatial straight-line distance between each marker is kept within a preset range of 2cm to 5cm. At the same time, the main incident path of the radiotherapy rays and the avoidance scheme of the surrounding important organs at risk are planned. After the implantation site design is completed, the corresponding puncture implantation path planning parameters are output, clarifying the needle insertion angle, needle insertion depth, and avoidance structure, so as to ensure the operational safety and positional accuracy of the marker implantation process.

[0028] This invention also includes a precise quantification and correction step for radiotherapy positioning deviation. Based on the cone-beam CT image data acquired before radiotherapy, and based on the actual spatial position of markers in the scan images and the reference position of markers in the radiotherapy plan, a quantitative calculation formula for comprehensive target positioning deviation is introduced: ; in This represents the overall positioning deviation value of the patient's tumor target area. The linear positional deviation of the marker in the left-right direction. The linear positional deviation of the marker in the front-to-back direction. The linear positional deviation of the marker in the head-to-feet direction. The comprehensive rotational deviation angle of the marker in three-dimensional space. The equivalent sphere diameter of the tumor target area is used. By quantitatively calculating the positioning deviation, linear deviation and rotational deviation can be integrated into the comprehensive deviation assessment system. This accurately quantifies the positional deviation in all dimensions during patient positioning, providing a clear quantitative basis for patient positioning correction. The corresponding correction range of the six-dimensional treatment bed can be determined based on the comprehensive deviation value, ensuring that the actual position of the tumor target area is completely consistent with the preset position in the treatment plan during each radiotherapy session. This significantly improves the accuracy of radiotherapy dose delivery and reduces the medical risks of missed radiation to the target area and excessive radiation to organs at risk.

[0029] In the preparation steps of the biodegradable radiopaque ceramic marker of the present invention, the biodegradable ceramic matrix material adopts one or more composites of β-tricalcium phosphate, calcium silicate, and magnesium-based bioceramics. The doped radiopaque element adopts one or more high atomic number elements of barium, bismuth, strontium, and tantalum. The mass doping ratio of the radiopaque element is controlled between 5% and 20%. The morphology of the marker is set as cylindrical, spherical, or sheet-like. The diameter of the marker is controlled between 1 mm and 3 mm, and the length is controlled between 3 mm and 10 mm. The surface of the marker is provided with a connected microporous structure. The pore size of the micropore is controlled between 50 μm and 200 μm, which can promote the ingrowth of surrounding human tissue into the marker after implantation and reduce the probability of the marker shifting or falling off within the preset radiotherapy cycle.

[0030] In the entire process of preparing the biodegradable and developable ceramic markers of this invention, the mixing step uses a wet ball milling process to uniformly mix the ceramic matrix powder and the developing element powder. Anhydrous ethanol is used as the ball milling medium. After ball milling, spray drying is performed to obtain a mixed powder with excellent flowability. In the molding step, dry injection molding or photopolymerization 3D printing process is used to prepare the marker preform. In the high-temperature sintering step, the sintering temperature is controlled between 1000℃ and 1300℃. During the sintering process, the heating rate and holding time are precisely controlled to regulate the grain size and internal porosity of the marker ceramic matrix. In the surface treatment step, sandblasting or chemical etching process is used to adjust the surface microporous structure and roughness. In the sterilization step, ethylene oxide sterilization or high-temperature and high-pressure steam sterilization is used. After sterilization, the product is sealed and packaged in a sterile environment.

[0031] The target area imaging data of this invention is image data of a marker implanted via coaxial puncture needle minimally invasively, acquired by a large-aperture CT or ultrasound device. The puncture and implantation path of the marker is a pre-planned path that avoids major blood vessels, nerve bundles and important functional organs. The image data includes thin-slice scan data in three dimensions: axial, coronal and sagittal, used to confirm the final implantation position and spatial distribution of the marker, and to verify that the marker position conforms to the preset plan, without displacement, dislodgement, or puncture-related bleeding or infection complications.

[0032] In the radiotherapy target delineation and treatment planning steps of this invention, based on the high-contrast imaging characteristics of markers in CT images without metal artifacts, rigid registration of the image coordinate system and the radiotherapy coordinate system is completed, with the spatial error of registration controlled within 0.5mm. Combining the plain CT and enhanced CT image information of the tumor lesion, the gross tumor target area, clinical target area, and planned target area are accurately delineated layer by layer. At the same time, the extent of organs at risk around the tumor and the maximum radiation dose limit are defined. Based on the delineated target area, intensity-modulated radiotherapy (IMRT) plan parameters or stereotactic radiotherapy (SRT) plan parameters are formulated to ensure that the prescription dose coverage of the planned target area reaches a preset standard of over 95%.

[0033] In the calculation of positioning correction parameters in this invention, the cone-beam CT image data used is real-time image data acquired by an airborne cone-beam CT scanner. The three-dimensional spatial position of the marker is automatically located through an image recognition algorithm and automatically compared with the reference position of the marker in the radiotherapy planning system. The full-dimensional positioning deviation of the target area is calculated. When the overall positioning deviation exceeds the preset threshold of 0.3mm, the position correction parameters of the six-dimensional treatment bed are generated for automatic position correction of the treatment bed. After the correction is completed, the deviation verification result is output. At the same time, the position information of the marker and the actual irradiation parameters can be recorded to complete the position information traceability and dose delivery record of the entire radiotherapy cycle.

[0034] The follow-up imaging data of this invention consists of CT images collected at 1 month, 3 months, 6 months, and 12 months after the completion of the entire radiotherapy cycle. Based on the follow-up imaging data, the degradation data of the marker in vivo, the lesion changes in the tumor target area, and the tissue reaction data in the marker implantation area are extracted and output. The marker can be gradually degraded in vivo into inorganic ions such as calcium and phosphorus, which are harmless to the human body and can be absorbed by human tissues or excreted through metabolism. After the marker is completely degraded, there is no need for targeted imaging monitoring. The entire process does not require a second surgery to remove the marker, reducing the medical burden, surgical risks, and physical and mental suffering of patients in clinical applications.

[0035] The following two examples further illustrate the specific implementation of this system: Example 1 This embodiment validates the target localization data processing method for stereotactic radiotherapy of early-stage non-small cell lung cancer based on the present invention. It is applied to the target localization scenario of stereotactic radiotherapy for early-stage non-small cell lung cancer. The tumor lesion is presumably located in the upper lobe of the right lung, with a maximum diameter of 2.2 cm and a pathological type of lung adenocarcinoma. The presumed radiotherapy cycle is 6 weeks, consisting of 8 fractionated irradiations. The core objective is to verify that this method can achieve sub-millimeter-level precise localization of the tumor target, ensuring accurate execution of stereotactic radiotherapy planning parameters, and simultaneously verifying the effectiveness of the biodegradable marker that does not require secondary surgical removal. This embodiment fully covers all technical solutions of the method, and all steps correspond completely to the overall method design, with no technical content exceeding the design scope.

[0036] This embodiment implements a radiotherapy target localization method based on biodegradable radioactive ceramic markers. First, the parameters of the biodegradable radioactive ceramic markers are customized. Based on the preset 6-week radiotherapy cycle, the physiological environmental characteristics of lung lesions, and the parameters affecting respiratory movement, the marker matrix material is determined to be β-tricalcium phosphate composite calcium silicate, the radioactive element is bismuth with a mass doping ratio of 12%, the marker morphology is cylindrical with a diameter of 1.5 mm and a length of 5 mm, the internal interconnected porosity is set to 15%, and the target degradation cycle is set to 8 months, so that the marker maintains structural stability throughout the radiotherapy cycle and can be gradually and completely degraded in vivo after the radiotherapy is completed.

[0037] After the marker parameters were determined, standardized preparation was completed. A wet ball milling process was used to uniformly mix the ceramic matrix powder and bismuth element powder. Anhydrous ethanol was used as the milling medium, and the milling time was 4 hours. After milling, spray drying was performed to obtain a mixed powder with excellent flowability. A dry-press molding process was used to prepare the marker preform. The molding pressure was set to 80 MPa, and the holding time was 30 seconds. After the preform was prepared, it was placed in a high-temperature sintering furnace for sintering. The sintering temperature was set to 1150℃, the heating rate was controlled at 5℃ per minute, and the holding time was 2 hours. After cooling in the furnace, it was removed and the surface was treated with sandblasting to achieve micropores, controlling the surface micropore diameter to be around 100 μm. The final marker was sterilized with ethylene oxide and sealed and packaged under sterile conditions.

[0038] In this embodiment, the markers are implanted into the target area reference region around the tumor lesion according to the preset plan. Imaging data of the implantation process under real-time guidance of large-aperture CT or ultrasound are obtained. Before implantation, the implantation point design is optimized based on the three-dimensional spatial morphology data of the tumor lesion and the distribution data of the surrounding lung tissue, bronchi, and major blood vessels. Three implantation points with non-coplanar spatial distribution are determined. The spatial straight-line distance between each marker is controlled at about 3 cm. The puncture path avoids major blood vessels, bronchi, and important functional areas. The implantation points are located in the normal lung tissue around the head, abdomen, and back of the tumor lesion, respectively. After implantation, axial, coronal, and sagittal thin-slice CT image data are obtained to confirm that the position of the three markers conforms to the preset plan and that there are no puncture-related complications such as displacement, detachment, pneumothorax, or bleeding.

[0039] Large-aperture CT scans of the entire chest were acquired 24 hours after marker implantation, with a slice thickness of 1 mm. Based on the high-contrast imaging characteristics of the markers (no artifacts), rigid registration between the image coordinate system and the radiotherapy coordinate system was achieved, with spatial registration error controlled within 0.5 mm. Combining plain and enhanced CT image information, precise delineation of the gross tumor target area, clinical target area, and planned target area was completed. Simultaneously, the extent of surrounding normal lung tissue, trachea, esophagus, spinal cord, and other organs at risk was defined, and maximum dose limits for each organ at risk were set. Based on the spatial relationship between the delineated target area and the markers, personalized stereotactic radiotherapy planning parameters were developed, determining the incident angle of the radiotherapy rays, the fractionated dose, and the total number of fractions. The prescribed dose was set at 12 Gy per fraction, for a total of 8 fractions. The target dose distribution scheme was optimized to ensure complete coverage of the planned target area by the high-dose radiotherapy zone, achieving a prescribed dose coverage rate of over 95%, while controlling the dose to each organ at risk within safe limits.

[0040] Before each radiotherapy session, the system acquires airborne cone-beam CT chest images. After scanning, the system automatically locates the three-dimensional spatial positions of three markers using an image recognition algorithm. These positions are then automatically compared with the reference positions of the markers in the radiotherapy planning system to calculate the full-dimensional positioning deviation of the target area. When the overall positioning deviation exceeds a preset threshold of 0.3 mm, position correction parameters for the six-dimensional treatment bed are generated for automatic position correction of the treatment bed. After correction, the system acquires image data from a second scan to verify that the deviation value is within the threshold range. The system can simultaneously record the position information of the markers and the irradiation execution parameters, thus completing the position information traceability and dose delivery record for the entire radiotherapy cycle.

[0041] After completing the entire radiotherapy cycle, chest CT follow-up imaging data were obtained at 1 month, 3 months, 6 months, and 12 months. Data on the degradation of the marker in vivo and the changes in lesions in the tumor target area were extracted and verified. Follow-up imaging data at 6 months post-treatment showed that the marker had significantly degraded. Follow-up imaging data at 12 months post-treatment showed that the marker had completely degraded in vivo. There was no abnormal tissue reaction in the implantation area and no signs of tumor recurrence. The entire process did not require a second surgery to remove the marker.

[0042] Table 1. Performance Comparison of the Invention's Data Processing Method and Traditional Metal Marker Localization Method in Lung Tumor Radiotherapy Scenarios. Table 1 visually demonstrates the comprehensive advantages of the data processing method of this invention in stereotactic radiotherapy for lung tumors. Traditional metallic markers produce severe artifacts in CT images, interfering with the accurate delineation of the target area and organs at risk. Furthermore, they are non-degradable, requiring secondary surgery for removal, and long-term retention can easily cause tissue reactions, failing to meet the clinical needs of high-precision radiotherapy. The data processing method of this invention uses degradable ceramic markers that produce no artifacts, enabling precise delineation of the target area and accurate positioning correction. The degradation cycle precisely matches the radiotherapy cycle, eliminating the need for secondary surgery, significantly reducing the incidence of tissue reactions, and fully meeting the high-precision and high-safety clinical requirements of stereotactic radiotherapy.

[0043] Example 2 This embodiment validates the target localization data processing method for adjuvant intensity-modulated radiotherapy (IMRT) after cervical cancer surgery, based on the present invention. It is applied to a target localization scenario for adjuvant IMRT after cervical cancer surgery, specifically to cases with high-risk factors for pelvic lymph node metastasis following cervical squamous cell carcinoma surgery. The preset radiotherapy cycle is 5 weeks, consisting of 25 fractionated irradiations. The core objective is to verify that this method can achieve precise localization and stable tracking of the pelvic clinical target area, ensuring uniform dose distribution of IMRT planning parameters, and simultaneously verifying the effectiveness of the biodegradable markers that do not require secondary surgical removal. This embodiment fully covers all technical solutions of the method, with all steps completely corresponding to the overall method design, and no technical content exceeding the design scope.

[0044] This embodiment implements a radiotherapy target localization method based on biodegradable radioactive ceramic markers. First, the parameters of the biodegradable radioactive ceramic markers are customized. Based on the preset parameters of the physiological environment of the pelvic tissues and the positional influence parameters of intestinal peristalsis and bladder filling during the entire 5-week radiotherapy cycle, the marker matrix material is determined to be magnesium-based bioceramic, the radioactive element is tantalum with a mass doping ratio of 8%, the marker morphology is cylindrical with a diameter of 2 mm and a length of 6 mm, the internal interconnected porosity is set to 12%, and the target degradation period is set to 6 months. This ensures that the marker maintains a stable spatial position and radioactive properties throughout the entire radiotherapy cycle and can be gradually and completely degraded in vivo after the radiotherapy is completed.

[0045] After the marker parameters were determined, standardized preparation was completed. A wet ball milling process was used to uniformly mix magnesium-based ceramic powder and tantalum element powder. Anhydrous ethanol was used as the milling medium, and the milling time was 6 hours. After milling, spray drying was performed to obtain the mixed powder. A marker preform was prepared using a photopolymerization 3D printing process. After the preform was prepared, it was placed in a high-temperature sintering furnace for sintering. The sintering temperature was set to 1200℃, the heating rate was controlled at 3℃ per minute, and the holding time was 3 hours. After cooling in the furnace, it was taken out and the surface micropores were treated using a chemical etching process. The surface micropore diameter was controlled to be about 80μm. The final marker was sterilized by high temperature and high pressure steam and sealed and packaged in a sterile environment.

[0046] In this embodiment, the markers are implanted into the pelvic target area reference region according to the preset plan. Imaging data of the implantation process under real-time guidance of ultrasound and CT are obtained. Before implantation, the three-dimensional spatial morphology data of the pelvic target area and the distribution data of the surrounding bladder, rectum, small intestine and iliac vessels are used to optimize the design of the implantation points. Four implantation points with non-coplanar spatial distribution are determined. The spatial straight-line distance between each marker is controlled at about 4 cm. The puncture path avoids the iliac vessels, bladder, rectum and surrounding nerve bundles. The implantation points are located in the pelvic soft tissue in the left anterior, left posterior, right anterior and right posterior directions of the pelvic target area. After implantation, axial, coronal and sagittal thin-slice CT image data are obtained to confirm that the position of the four markers conforms to the preset plan and that there are no puncture-related complications such as displacement, dislodgement, bleeding and infection.

[0047] Large-aperture CT thin-slice images of the entire pelvic cavity were acquired 48 hours after marker implantation, with a slice thickness of 1 mm. Based on the high-contrast imaging characteristics of the markers (free of artifacts), rigid registration between the image coordinate system and the radiotherapy coordinate system was achieved, with spatial registration error controlled within 0.5 mm. Combining plain and enhanced CT image information, precise delineation of the pelvic clinical and planned target areas was completed. Simultaneously, the extent of surrounding organs at risk, such as the bladder, rectum, small intestine, femoral head, and spinal cord, was defined, and maximum dose limits for each organ at risk were set. Based on the spatial relationship between the delineated target area and the markers, personalized intensity-modulated radiotherapy (IMRT) planning parameters were developed, determining the incident angle of the radiation, the fractionated dose, and the total number of fractions. The prescribed dose was set at 2 Gy per fraction, for a total of 25 fractions. The target dose distribution scheme was optimized to ensure complete coverage of the planned target area by the high-dose radiation zone, achieving a prescribed dose coverage rate of over 95%, while controlling the dose to each organ at risk within safe limits.

[0048] Before each radiotherapy session, the system acquires pelvic imaging data from an onboard cone-beam CT scanner. After scanning, the system automatically locates the three-dimensional spatial position of four markers using an image recognition algorithm. This position is then automatically compared with the reference position of the markers in the radiotherapy planning system to calculate the full-dimensional positioning deviation of the target area. When the overall positioning deviation exceeds a preset threshold of 0.3 mm, position correction parameters for the six-dimensional treatment bed are generated for automatic position correction of the treatment bed. After correction, the system acquires image data from a subsequent scan to verify that the deviation value is within the threshold range. The system can simultaneously record the position information of the markers and the irradiation execution parameters, thus completing the position information traceability and dose delivery recording throughout the entire radiotherapy cycle.

[0049] After completing the entire radiotherapy cycle, pelvic CT follow-up imaging data were obtained at 1 month, 3 months, 6 months, and 12 months. Data on the degradation of the marker in vivo and the changes in lesions in the pelvic target area were extracted and verified. Follow-up imaging data at 3 months post-treatment showed that the marker had partially degraded. Follow-up imaging data at 12 months post-treatment showed that the marker had completely degraded in vivo. There was no abnormal tissue reaction in the implantation area and no signs of tumor recurrence in the pelvis. The entire process did not require a second surgery to remove the marker.

[0050] Table 2. Performance Comparison of the Invention's Data Processing Method and Traditional Metal Marker Localization Method in Postoperative Radiotherapy Scenarios for Cervical Cancer Table 2 clearly demonstrates the comprehensive advantages of the data processing method of this invention in the context of pelvic radiotherapy after cervical cancer surgery. Traditional metallic markers exhibit CT artifacts that interfere with the precise delineation of the pelvic target area and surrounding organs at risk. Their limited control over fractional positioning errors easily leads to uneven dose distribution in the target area, and their non-degradable nature poses a safety risk of long-term retention in the body, requiring secondary surgery for removal. The data processing method of this invention uses biodegradable ceramic markers that produce no artifacts, enabling precise delineation of the pelvic target area and accurate correction of fractional positioning, ensuring uniform dose distribution in the target area. It also possesses excellent tissue compatibility, with a degradation cycle precisely matching the radiotherapy cycle, eliminating long-term retention safety risks, and requiring no secondary surgery, thus fully meeting the clinical application needs of intensity-modulated pelvic radiotherapy.

[0051] refer to Figure 1This diagram illustrates the complete workflow of this radiotherapy target localization method from a macroscopic perspective. The process begins with a pre-defined assessment of tumor lesion characteristics and the setting of parameters throughout the radiotherapy cycle, as well as the personalized customization of marker parameters. This is followed by a standardized preparation stage, producing ceramic markers with excellent biocompatibility and imaging performance. Medical imaging data of the markers implanted around the lesion according to the pre-defined plan is obtained. The core step involves using large-aperture CT scans without artifacts to accurately delineate the target area, and using cone-beam CT images before each radiotherapy session to verify the position and calculate positioning correction parameters. Finally, the process extends to monitoring the marker degradation status after the entire radiotherapy cycle. The markers gradually and completely degrade in the body, achieving a closed loop that eliminates the need for secondary surgery for removal, significantly reducing the medical risks and patient burden in clinical applications.

[0052] Reference Figure 2 This figure highlights the reverse design and multi-parameter synergistic regulation mechanism of the marker's degradation characteristics. To ensure a perfect match between the marker's degradation cycle and the pre-set total duration of radiotherapy, the system constructs a degradation cycle regulation model based on pre-set lesion tissue metabolic characteristics and radiotherapy protocol parameters. Three parallel physical and chemical parameters—internal connectivity porosity, average grain size of the ceramic matrix, and the mass doping percentage of high atomic number imaging elements—comprehensively influence the degradation rate. This multi-dimensional parameter regulation strategy ensures that the marker remains structurally stable and clearly visualized during radiotherapy, and degrades safely and as scheduled after treatment.

[0053] Reference Figure 3 This diagram details the hardware manufacturing process of biodegradable and developable ceramic markers, presented in a phased swimlane diagram structure. First, in the mixing stage, the bioceramic matrix (such as tricalcium phosphate) and high atomic number developing elements (such as barium and bismuth) are wet-milled and spray-dried with anhydrous ethanol to ensure powder uniformity. Second, in the molding and sintering stage, a preliminary blank is prepared using dry molding or 3D printing, and then sintered at high temperatures under strict temperature control to regulate grain size and porosity. Finally, in the surface treatment and packaging stage, sandblasting or etching techniques are used to create a microporous structure suitable for tissue ingrowth, followed by sterilization with ethylene oxide or high-temperature, high-pressure autoclaves, ultimately achieving aseptic sealing and packaging.

[0054] Reference Figure 4This diagram uses a state machine model to clearly present the entire process logic of marker implantation site planning, path design, and image verification. It begins with a comprehensive preoperative planning phase: based on three-dimensional tumor morphology data, distribution data of organs at risk, and pre-defined radiation incidence paths, non-coplanar spatial distribution points are designed while ensuring the pre-defined straight-line distance range. This is followed by the implantation path planning and image-guided parameter design phase, clarifying the risk-avoidance needle insertion path for the coaxial puncture needle and planning the implantation points in the target reference area. Finally, the multi-dimensional image verification phase is entered, using axial, coronal, and sagittal thin-slice scanning image data to confirm that the markers have not fallen off or shifted and that their positions conform to the pre-defined plan, laying a solid positioning benchmark for subsequent target localization and radiotherapy planning.

[0055] refer to Figure 5 This figure highlights the precise quantification of target positioning deviation and the closed-loop generation logic of correction parameters. Using the "preset reference position of the markers in the radiotherapy planning system" and the "actual position of the markers extracted from real-time images from airborne cone-beam CT scans" as dual inputs, the system innovatively integrates linear displacement deviation on the spatial coordinate axes with rotational deviation in three-dimensional space to calculate a comprehensive positioning deviation measure. The system sets strict deviation thresholds; once the comprehensive deviation exceeds the limit, six-dimensional compensation parameters are immediately generated and output to the six-dimensional treatment bed to complete automated position correction. After correction, a second scan is triggered for verification, forming a tight control loop that fundamentally ensures target positioning accuracy and avoids the risk of target dose deviation.

[0056] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for radiotherapy target localization based on biodegradable radiopaque ceramic markers, characterized in that, Includes the following steps: Based on the preset tumor lesion parameters and the full cycle parameters of radiotherapy, the parameters of the biodegradable radioactive ceramic marker are customized, and the matrix material ratio, doping ratio of radioactive elements, morphology and size, internal porosity and target degradation cycle of the marker are determined, so that the in vivo degradation cycle of the marker matches the preset full cycle of radiotherapy. The markers were prepared by doping high atomic number developing elements into a biodegradable ceramic matrix material. The ceramic markers were prepared through a standardized process involving powder mixing, pre-pressing, high-temperature sintering, surface micropore treatment, sterilization and packaging. Acquire thin-layer image data of the target area where the ceramic markers are implanted, wherein the ceramic markers are at least three and are distributed in a non-coplanar spatial distribution around the tumor lesion in the target reference area; Based on the artifact-free imaging characteristics of markers in the thin-layer imaging data, the precise registration of the image coordinate system and the radiotherapy coordinate system is completed. Combined with the plain and enhanced imaging information of the tumor lesion, the precise layer delineation of the radiotherapy target area and the scope of surrounding organs at risk are completed. Based on the spatial relationship between the delineated target area and the markers, radiotherapy planning parameters are formulated to determine the incident angle of the radiotherapy rays, the dose of each irradiation, the total number of irradiation sessions, and the dose distribution scheme of the target area, so that the high-dose area of ​​radiotherapy completely covers the target area while controlling the radiation dose to organs at risk within safe limits. Acquire cone-beam CT image data before radiotherapy, and calculate target placement correction parameters based on the deviation between the actual spatial position of the markers in the images and the reference position in the radiotherapy plan, which are used for six-dimensional position correction of the radiotherapy equipment. Acquire follow-up imaging data after the completion of the entire radiotherapy cycle, extract and output data on the degradation of markers in vivo and changes in lesions in the tumor target area.

2. The method for radiotherapy target localization based on biodegradable radiopaque ceramic markers according to claim 1, characterized in that, It also includes a precise matching and optimization step for the marker degradation cycle and the radiotherapy cycle. In the marker parameter customization stage, based on the preset radiotherapy fractionation plan, the metabolic characteristics of the lesion tissue, and the physiological environmental characteristics of the implantation area, a calculation formula for regulating the marker degradation cycle is introduced: ； in The actual complete degradation cycle of the marker in human tissues, This is the preset total duration of the entire radiotherapy cycle. The weighting coefficient for the effect of marker porosity on degradation rate. The internal interconnected porosity of the marker. The weighting coefficient for the effect of ceramic matrix grain size on degradation rate. The average grain size of the marker ceramic matrix, The weighting coefficient represents the effect of the doping ratio of developing elements on the degradation rate. This represents the mass doping percentage of the developing element in the ceramic matrix.

3. The method for radiotherapy target localization based on biodegradable radiopaque ceramic markers according to claim 1, characterized in that, It also includes a multi-dimensional optimization layout step for marker implantation sites. Based on the three-dimensional spatial morphology data of the tumor lesion, the distribution data of surrounding organs at risk, and the preset incident path of the radiotherapy rays, the optimized design of the marker implantation sites is completed. Implantation sites with non-coplanar spatial distribution are determined so that the spatial straight-line distance between each marker is kept within a preset range of 2cm to 5cm. At the same time, the main incident path of the radiotherapy rays and the avoidance scheme of surrounding important organs at risk are planned. After the implantation site design is completed, the corresponding puncture implantation path planning parameters are output.

4. The method for radiotherapy target localization based on biodegradable radiopaque ceramic markers according to claim 1, characterized in that, It also includes a precise quantification step for radiotherapy positioning deviation, which introduces a quantitative calculation formula for comprehensive target positioning deviation based on the actual spatial position of markers in the acquired images and the reference position of markers in the radiotherapy plan: ； in This represents the overall positioning deviation value of the patient's tumor target area. The linear positional deviation of the marker in the left-right direction. The linear positional deviation of the marker in the front-to-back direction. The linear positional deviation of the marker in the head-to-feet direction. The comprehensive rotational deviation angle of the marker in three-dimensional space. The equivalent sphere diameter of the tumor target area.

5. The method for radiotherapy target localization based on biodegradable radiopaque ceramic markers according to claim 1, characterized in that, In the preparation steps of the biodegradable developing ceramic marker, the biodegradable ceramic matrix material adopts one or more composites of β-tricalcium phosphate, calcium silicate, and magnesium-based bioceramics. The developing element doped adopts one or more high atomic number elements of barium, bismuth, strontium, and tantalum. The mass doping ratio of the developing element is controlled between 5% and 20%. The morphology of the marker is set as cylindrical, spherical, or sheet-like. The diameter of the marker is controlled between 1 mm and 3 mm, and the length is controlled between 3 mm and 10 mm. The surface of the marker is provided with a connected microporous structure, and the pore size of the micropore is controlled between 50 μm and 200 μm.

6. The method for radiotherapy target localization based on biodegradable radiopaque ceramic markers according to claim 1, characterized in that, In the entire process of preparing the biodegradable and developable ceramic marker, the mixing step uses a wet ball milling process to uniformly mix the ceramic matrix powder and the developing element powder. Anhydrous ethanol is used as the ball milling medium. After ball milling, spray drying is performed to obtain a mixed powder with excellent flowability. The molding step uses dry injection molding or photopolymerization 3D printing to prepare the marker preform. The sintering temperature in the high-temperature sintering step is controlled between 1000℃ and 1300℃. During the sintering process, the heating rate and holding time are precisely controlled to regulate the grain size and internal porosity of the marker ceramic matrix. The surface treatment step uses sandblasting or chemical etching to adjust the surface microporous structure and roughness. The sterilization step uses ethylene oxide sterilization or high-temperature and high-pressure steam sterilization. After sterilization, the product is sealed and packaged in a sterile environment.

7. The method for radiotherapy target localization based on biodegradable radiopaque ceramic markers according to claim 1, characterized in that, The thin-slice imaging data of the target area is image data acquired by a large-aperture CT device or ultrasound device, including markers implanted with a coaxial puncture needle. The puncture and implantation path of the markers is a pre-planned path that avoids major blood vessels, nerve bundles and important functional organs. The image data includes thin-slice scan data in three dimensions: axial, coronal and sagittal.

8. The method for radiotherapy target localization based on biodegradable radiopaque ceramic markers according to claim 1, characterized in that, In the radiotherapy target delineation and treatment planning steps, based on the high-contrast imaging characteristics of markers without metal artifacts in CT images, rigid registration of the image coordinate system and the radiotherapy coordinate system is completed. Combining the plain CT and enhanced CT image information of the tumor lesion, the gross tumor target area, clinical target area, and planned target area are accurately delineated layer by layer. At the same time, the extent of organs at risk around the tumor and the maximum radiation dose limit are defined. Based on the delineated target area, intensity-modulated radiotherapy planning parameters or stereotactic radiotherapy planning parameters are formulated.

9. A method for radiotherapy target localization based on biodegradable radiopaque ceramic markers according to claim 1, characterized in that, In the positioning verification and correction step, the cone-beam CT image data is real-time image data acquired by airborne cone-beam CT. The three-dimensional spatial position of the marker is automatically located through the image recognition algorithm and automatically compared with the reference position of the marker in the radiotherapy planning system. The full-dimensional positioning deviation of the target area is calculated. When the overall positioning deviation exceeds the preset threshold of 0.3mm, the position correction parameters of the six-dimensional treatment bed are generated for automatic position correction of the treatment bed. After the correction is completed, the deviation verification result is output, and the position information of the marker and the irradiation parameters are recorded at the same time.

10. A method for radiotherapy target localization based on biodegradable radiopaque ceramic markers according to claim 1, characterized in that, The follow-up imaging data consists of CT images collected at 1 month, 3 months, 6 months, and 12 months after the completion of the entire radiotherapy cycle. Based on the follow-up imaging data, data on the degradation of the marker in vivo, changes in lesions in the tumor target area, and tissue response in the marker implantation area are extracted and output.

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