Radiotherapy equipment for angle adjustment between treatment fractions during multi-fraction radiotherapy

Abstract

The invention provides radiotherapy equipment for angle adjustment between treatment fractions during multi-fraction radiotherapy. The radiotherapy equipment comprises an angle selection unit, an angle adjustment unit and an angle adjustment unit, wherein the angle selection unit is used for executing irradiation angle selection of initial treatment fractions; an angle adjustment unit for performing angle adjustment in a subsequent treatment fraction based on the irradiation angle of the initial treatment fraction; and the monitoring and adjusting unit is used for executing dose accumulation, monitoring and adjustment on the basis of the irradiation angle of the initial treatment fraction and the adjusted angle in the subsequent treatment fraction.

Description

Technical Field

[0001] The present invention relates to the field of medical equipment, and in particular to a radiotherapy device for adjusting the angle between treatment fractions during multi-fraction radiotherapy. The device can achieve multi-angle precise irradiation by adjusting the irradiation angle between different treatment fractions on an accelerator device with a limited number of heads or a fixed irradiation angle. Background Art

[0002] Radiotherapy is a treatment method that uses radiation (such as α, β, γ rays produced by radioisotopes, x-rays, electron beams, proton beams and other particle beams, etc.) for treatment. It is generally used to treat malignant tumors. Radiotherapy is widely used in tumor treatment. It destroys the DNA of tumor cells through high-energy radiation, thereby inhibiting the growth and spread of tumors.

[0003] IMRT (Intensity modulated radiotherapy) is a highly sophisticated tumor treatment technology. The process of formulating the treatment plan is extremely complex, and the selection of the radiation field angle is one of the key factors to ensure the treatment effect. IMRT uses a combination of radiation fields at different angles to allow radiation to enter the patient's body from multiple directions, forming a cross-coverage dose distribution, thereby concentrating on irradiating the tumor and effectively avoiding key organs. This multi-angle radiation field design not only improves the local control rate of the tumor, but also significantly reduces the risk of side effects caused by radiotherapy.

[0004] In clinical practice, the choice of field angle mainly depends on the anatomical location, shape, size of the tumor and its relative position to surrounding critical organs (such as the spinal cord, heart, lungs, bladder, etc.). Usually, this selection process is completed by experienced radiation therapy physicists in collaboration with clinicians, combined with computer-assisted dose distribution optimization algorithms to develop the best treatment plan. Studies have shown that among the 8,143 IMRT treatment plans of the Department of Radiation Oncology, Cancer Hospital, Chinese Academy of Medical Sciences from 2012 to 2022, most plans usually require the use of 5 to 9 field angles, while some complex treatment plans even require up to 11 to 13 field angles to achieve optimal tumor coverage and protection of critical organs.

[0005] In traditional IMRT treatment, all treatment fractions usually use exactly the same irradiation angles. These field angles remain consistent throughout the treatment process to form a stable, multi-angle dose distribution to maximize coverage of the tumor area and protect critical organs. This multi-field angle IMRT plan achieves precise dose control by repeating the same irradiation angle in each treatment fraction. However, this method relies on the flexibility of the accelerator and the number of heads to enable each treatment fraction to provide multiple irradiation angles to achieve the ideal treatment effect.

[0006] For example, when treating head and neck tumors, due to the complex anatomical structure of this area, a more complex multi-angle field combination is usually required to avoid high-dose radiation exposure to critical structures such as nerves and blood vessels. When treating complex tumors such as lung cancer or rectal cancer, a reasonable multi-angle field design not only improves the dose coverage of the tumor, but also reduces radiation exposure to organs such as the heart, lungs, or bladder. Therefore, the selection of field angles in IMRT is not only a technical challenge, but also an important decision related to the patient's treatment effect and quality of life. Every detail needs to be carefully weighed to ensure the best tumor treatment effect and minimize damage to normal tissues.

[0007] With the continuous development of radiotherapy technology, new accelerator equipment, such as FLASH accelerator, has shown obvious advantages in certain clinical applications due to its efficient irradiation characteristics (such as ultrafast irradiation and extremely short treatment time). However, due to the limitations of mechanical design or irradiation conditions, these accelerators usually cannot provide more than 5 irradiation angles in a single treatment, which poses a challenge to the treatment of complex tumors. In addition to the limitations of these advanced equipment, some accelerators cannot achieve flexible rotation of the frame or multi-angle adjustment due to relatively backward technology. The design of traditional accelerator equipment is often limited by the fixed number of heads or irradiation angles, and cannot provide multi-angle field combination functions similar to modern IMRT accelerators. This technical limitation makes it difficult for these accelerators to achieve the therapeutic effect of traditional IMRT when treating complex tumors.

[0008] In these cases, due to the limitation of the number of heads or irradiation angles in a single treatment, these accelerators cannot optimize the dose distribution by flexibly adjusting the field angle, which to some extent affects the comprehensive coverage of the tumor and the protection of key organs. This not only increases the complexity of treatment, but also places higher demands on the treatment effect and quality of life of patients. Therefore, how to achieve a treatment effect comparable to that of traditional IMRT under limited irradiation angle conditions has become a technical problem that needs to be solved urgently. This not only involves the optimization of existing hardware, but also requires the development of new treatment plans to gradually optimize the irradiation angle in multiple treatment fractions to overcome the limitations of single treatment.

[0009] The following typical cases further demonstrate the limitations of existing technologies:

[0010] Case 1: Head and neck cancer patient

[0011] The patient was a 60-year-old male who was diagnosed with left-sided nasopharyngeal carcinoma, with the tumor close to the spinal cord. Traditional IMRT plans usually require the design of 9 field angles to ensure that the tumor is fully covered while exposing the spinal cord to the lowest radiation dose. This multi-angle field design can focus the dose on the tumor area through cross-ray paths without causing excessive radiation to the spinal cord.

[0012] However, when using the FLASH accelerator for treatment, due to the fixed number of heads and the inability to adjust the field angle, the treatment plan can only use a few fixed field angles, resulting in higher radiation doses to the spinal cord, significantly increasing the risk of radiation myelitis in patients. This case shows that the fixed field angle design has significant limitations when treating complex tumors close to critical organs, which may affect patient safety and treatment outcomes.

[0013] Case 2: Lung cancer patient

[0014] The patient is a 70-year-old female who was diagnosed with lung cancer in the left upper lobe of the lung, with the tumor located close to the heart. Traditional IMRT plans usually require seven radiation field angles to ensure the dose coverage of the tumor while minimizing radiation to the heart. Through multi-angle radiation field design, the treatment plan can avoid the heart while focusing on the tumor area.

[0015] However, under the fixed field angle of the FLASH accelerator, the treatment plan cannot be flexibly adjusted, resulting in some rays directly passing through the heart area, increasing the radiation exposure of the heart. This situation may cause patients to face a higher risk of radiation heart disease after treatment, affecting the patient's long-term health.

[0016] Case 3: Rectal cancer patient

[0017] The patient was a 55-year-old male who was diagnosed with rectal cancer. The tumor was located in the pelvic cavity, close to the bladder. The traditional IMRT plan was designed with five radiation field angles, with the goal of effectively covering the tumor while reducing the radiation dose to the bladder. Through this multi-angle radiation field design, the treatment plan was able to focus most of the dose on the tumor while avoiding the bladder as much as possible.

[0018] However, in the application of FLASH accelerator, due to the fixed field angle, the treatment plan cannot be adjusted as flexibly as traditional IMRT, resulting in a higher radiation dose to the bladder. This not only increases the risk of radiation cystitis in patients, but may also affect the quality of life of patients and even require additional medical intervention to manage side effects.

[0019] These cases show that although the fixed field angle design of the FLASH accelerator simplifies the treatment process to a certain extent, it has significant limitations in the treatment of complex tumors, especially in cases with complex anatomical structures or special tumor locations. These limitations may lead to poor treatment effects and even pose a threat to the patient's health.

[0020] Therefore, the field of radiotherapy urgently needs a new technical solution that can maintain the high-efficiency treatment characteristics of the FLASH accelerator while overcoming its fixed field angle limitation and providing treatment effects comparable to or even better than traditional IMRT. This new technology should be able to flexibly adjust the field angle combination in the treatment fractions to optimize the dose distribution, ensure that the tumor is adequately covered by the dose, and protect the surrounding critical organs. Summary of the invention

[0021] The technical problem to be solved by the present invention is to provide a radiotherapy device based on inter-fraction angle adjustment that can achieve better planning quality in response to the above-mentioned defects in the prior art. The device can flexibly adjust the field angle combination in the treatment fractions to optimize the dose distribution and ensure that the tumor is adequately covered by the dose while protecting the surrounding critical organs.

[0022] According to one aspect of the present invention, a radiotherapy device based on inter-fraction angle adjustment is provided, the device comprising:

[0023] Angle selection unit: used to select the irradiation angle for the initial treatment fractions;

[0024] Angle adjustment unit: used to perform angle adjustment in subsequent treatment fractions based on the irradiation angle of the initial treatment fraction;

[0025] Monitoring and adjustment unit: used to perform dose accumulation, monitoring and adjustment based on the irradiation angle of the initial treatment fraction and the adjusted angle in the subsequent treatment fractions.

[0026] Preferably, the angle adjustment unit includes a data input unit and a control unit; the data input unit is used to input big data of IMRT treatment plan using a single irradiation head; the control unit retrieves the IMRT plan reality of the case closest to the object to be treated from the IMRT treatment plan big data according to the object to be treated, and optimizes based on the retrieved IMRT plan reality to determine the number of irradiation cycles of the irradiation head and the irradiation angle during each irradiation cycle.

[0027] Preferably, the control unit is used to perform the following steps:

[0028] In the retrieved IMRT plan, a single irradiation head uses N irradiation angles A1-AN for multiple irradiations. The control unit uses an adaptive simulated annealing method to calculate the following objective function values ​​for the number of irradiations of the irradiation head and the irradiation angle during each irradiation:

[0029] minf(β)

[0030] Among them, β is the angle of the frame relative to the area to be irradiated during the round irradiation, M is the number of heads, L is the number of round irradiations of the heads, and B is the angle of the irradiation direction of the heads in each round irradiation relative to the frame.

[0031] Preferably, the number of heads is between 3 and 5.

[0032] Preferably, the number of times the head is illuminated is between 1 and 4 times.

[0033] Preferably, the IMRT treatment plan big data is case big data related to the hospital's IMRT treatment plan.

[0034] Preferably, after rotational irradiation, the fractionated doses at different gantry angles and the final synthesized total dose of the target area both meet the prescription dose requirements.

[0035] Preferably, the angle adjustment unit introduces a new angle combination in subsequent treatment fractions by rotating the gantry or adjusting the irradiation angle to supplement the tumor area not covered in the initial fractions and further reduce the radiation exposure to normal tissues.

[0036] Preferably, the monitoring and adjustment unit monitors the dose distribution of each fraction in real time during the entire treatment process, and cumulatively calculates the total radiation dose to the tumor and key organs; wherein the dose delivered in each treatment fraction is converted into an equivalent 2Gy fractional dose EQD2:

[0037]

[0038] Where D represents the total dose (Gy), d is the fractional dose in each treatment fraction (Gy), and α / β is a parameter for a specific tissue or tumor that represents the radiobiological response characteristics of the tissue. For tumors, typical α / β values ​​are usually around 10 Gy, while for normal tissues, especially those with late responses, α / β values ​​are usually between 2 and 4 Gy;

[0039] Furthermore, after calculating the EQD2 for each treatment fraction, the monitoring and adjustment unit adds up these values ​​to obtain the total EQD2 for the entire treatment process, and then compares this cumulative EQD2 with the clinical prescription requirements to ensure that the combined dose of all treatment fractions meets the treatment goals.

[0040] Preferably, the radiotherapy equipment based on inter-fraction angle adjustment also includes: an evaluation unit: used to perform dose evaluation after the treatment is completed, to comprehensively evaluate the entire treatment process after all treatment fractions are completed, to analyze the dose coverage of the tumor and the protection of key organs, to ensure that the treatment has achieved the expected results through comprehensive analysis of the cumulative dose, and to provide reference for treatment plans for similar cases in the future based on these data, to further optimize the radiotherapy plan.

[0041] Preferably, the radiotherapy device based on inter-fraction angle adjustment is a FLASH radiotherapy device.

[0042] The radiotherapy equipment based on inter-fraction angle adjustment provided by the present invention can achieve multi-angle precise irradiation by adjusting the irradiation angle between different treatment fractions on an accelerator device with a limited number of heads or a fixed irradiation angle. It can flexibly adjust the field angle combination in the treatment fractions to optimize the dose distribution, ensure that the tumor is adequately covered by the dose, and protect the surrounding critical organs at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] A more complete understanding of the present invention and its attendant advantages and features will be more readily appreciated by reference to the following detailed description taken in conjunction with the accompanying drawings, in which:

[0044] Figure 1 The overall block diagram of a radiotherapy device for adjusting the angle between treatment fractions during multi-fractionation radiotherapy according to a first preferred embodiment of the present invention is schematically shown.

[0045] Figure 2A The original IMRT plan in a specific example is schematically shown.

[0046] Figure 2B The improved IMRT plan is schematically shown.

[0047] Figure 2C The improved IMRT plan is schematically shown.

[0048] Figure 2D The improved IMRT plan is schematically shown.

[0049] Figure 3A An original IMRT plan in another specific example is schematically shown.

[0050] Figure 3B The improved IMRT plan is schematically shown.

[0051] Figure 3C The improved IMRT plan is schematically shown.

[0052] Figure 4 The overall block diagram of a radiotherapy device for adjusting the angle between treatment fractions during multi-fractionation radiotherapy according to a second preferred embodiment of the present invention is schematically shown.

[0053] It should be noted that the drawings are used to illustrate the present invention, rather than to limit the present invention. Note that the drawings showing the structures may not be drawn to scale. In addition, in the drawings, the same or similar elements are marked with the same or similar reference numerals. DETAILED DESCRIPTION

[0054] In order to make the contents of the present invention clearer and easier to understand, the contents of the present invention are described in detail below in conjunction with specific embodiments and drawings.

[0055] In order to solve the above problems, the present invention provides an irradiation method for adjusting the angle between radiotherapy fractions. By dynamically adjusting the irradiation angle between different treatment fractions, the limitation of insufficient irradiation angle in a single treatment is made up, thereby achieving the same treatment effect as the combination of multiple fields in traditional IMRT. The method of the present invention is applicable to a variety of accelerator equipment, especially when the number of heads or irradiation angles are limited, and can effectively improve the accuracy and safety of treatment.

[0056] Specific embodiments of the present invention are described below.

[0057] <First Embodiment>

[0058] Figure 1 The overall block diagram of the radiotherapy device for adjusting the angle between treatment fractions in multi-fraction radiotherapy according to the first preferred embodiment of the present invention is schematically shown. For example, the radiotherapy device for adjusting the angle between treatment fractions in multi-fraction radiotherapy is a FLASH device.

[0059] like Figure 1 As shown, the radiotherapy device for adjusting the angle between treatment fractions during multi-fractionation radiotherapy according to a preferred embodiment of the present invention comprises: a data input unit 100, a control unit 200 and a plurality of irradiation heads 300 arranged on a frame.

[0060] The data input unit 100 is used to input big data of an IMRT treatment plan using a single irradiation head, such as big data of cases related to the hospital's IMRT treatment plan.

[0061] The control unit 200 retrieves the IMRT plan actual situation of the case closest to the object to be treated from the IMRT treatment plan big data according to the object to be treated, and optimizes based on the retrieved IMRT plan actual situation to control the number of irradiation cycles of the irradiation head 300 and the irradiation angle during each irradiation cycle.

[0062] Specifically, for example, the control unit 200 actually performs optimization based on the retrieved IMRT plan including:

[0063] In the retrieved IMRT plan, a single irradiation head uses N irradiation angles A1-AN (generally 4≤N≤9) for multiple irradiations. The control unit 200 uses an adaptive simulated annealing method (ASA) to calculate the following objective function value for the number of irradiations of the irradiation head 300 and the irradiation angle during each irradiation:

[0064] minf(β)

[0065] in,

[0066] Moreover, β is the angle of the frame relative to the area to be irradiated during rotation, M is the number of heads (for example, 3≤M≤5), L is the number of rotations of the heads, and B is the angle of the irradiation direction of the heads in each rotation relative to the frame.

[0067] It can be seen that the value of β should minimize the above formula. Therefore, in fact, the present invention uses as few irradiation cycles as possible to achieve an irradiation range that is as consistent as possible with the retrieved IMRT plan.

[0068] Preferably, the number of irradiation heads 300 is between 3 and 5.

[0069] Preferably, the number of irradiation cycles of the irradiation head 300 is between 1 and 4.

[0070] The present invention establishes a radiotherapy scheme with angle adjustment between fractions, that is, different gantry angles are used between different treatment fractions for the same patient, and multi-angle irradiation is achieved based on a fixed angle to achieve better plan quality. In the irradiation scheme proposed by the present invention, it is further arranged that, after rotation irradiation, the fractional doses of different gantry angles and the final synthesized total dose of the target area meet the prescription dose requirements.

[0071] <Example>

[0072] Example 1: For a lung cancer case, the original IMRT plan has field angles of 10°, 35°, 60°, 320°, and 345°. Figure 2A As shown in the photos.

[0073] Therefore, the rotation plan for different numbers of heads is as follows:

[0074] Number of heads M Number of rounds L Wheel angle set1 Wheel angle set2 3 2 50°、170°、270° 90°、210°、330° 4 2 10°、120°、160°、200° 40°、150°、200°、340° 5 1 0°、30°、160°、200°、330°

[0075] Specific as Figure 2B (Three aircraft heads were photographed twice), Figure 2C (Two rounds of photography of four aircraft heads), Figure 2D (Five aircraft heads in one rotation) as shown in the photo.

[0076] Example 2: For a rectal case, the original IMRT plan has 7 fields with angles of 0°, 50°, 100°, 150°, 210°, 260°, and 310°. Figure 3A As shown in the photos.

[0077] Therefore, the rotation plan for different numbers of heads is as follows:

[0078] Number of heads M Number of rounds L Wheel angle set1 Wheel angle set2 3 2 0°、120°、240° 50°、170°、290° 4 2 60°、110°、250°、310° 40°、150°、200°、340° 5 2 20°、50°、80°、210°、250° 110°、150°、280°、310°、340°

[0079] Specific as Figure 3B(Two rounds of photography of four aircraft heads), Figure 3C (Two shots of five aircraft heads) as shown in the photo.

[0080] The radiotherapy equipment based on inter-fraction angle adjustment provided by the present invention can achieve multi-angle precise irradiation by adjusting the irradiation angle between different treatment fractions on an accelerator device with a limited number of heads or a fixed irradiation angle. It can flexibly adjust the field angle combination in the treatment fractions to optimize the dose distribution, ensure that the tumor is adequately covered by the dose, and protect the surrounding critical organs at the same time.

[0081] <Second Embodiment>

[0082] According to another aspect of the present invention, the radiotherapy method with angle adjustment between fractions can be implemented in actual operation by the following units to ensure that the same treatment effect as traditional IMRT is achieved on an accelerator device with a limited number of heads or irradiation angles.

[0083] Figure 4 The overall block diagram of the radiotherapy device for adjusting the angle between treatment fractions in multi-fraction radiotherapy according to the second preferred embodiment of the present invention is schematically shown. For example, the radiotherapy device for adjusting the angle between treatment fractions in multi-fraction radiotherapy is a FLASH device.

[0084] like Figure 4 As shown, Figure 4 The radiotherapy device for adjusting the angle between treatment fractions during multi-fraction radiotherapy according to the second preferred embodiment of the present invention is schematically shown to include:

[0085] Angle selection unit 101: used to select the irradiation angle for the initial treatment fractions;

[0086] Specifically, before the first treatment fraction, a set of optimal irradiation angle combinations is selected based on the patient's anatomical structure, the specific conditions of the tumor, and previous treatment experience. This set of angles should cover the main areas of the tumor as much as possible and avoid critical organs as much as possible. To ensure the rationality of the angle selection, it is usually necessary to combine the patient's imaging data (such as CT, MRI) and computer-assisted dose distribution optimization algorithms for precise calculations. The selection of irradiation angles also refers to a large number of IMRT treatment plan databases, and a heuristic algorithm is used to prioritize key angles and establish a preliminary field distribution framework. These selected angles remain fixed throughout the initial fractions to ensure effective dose delivery.

[0087] Example: For a patient with left upper lobe lung cancer, five radiation field angles, such as 0°, 30°, 90°, 120° and 150°, may be selected for initial treatment fractionation to cover the tumor and avoid the heart and spinal cord.

[0088] Angle adjustment unit 102: used to perform angle adjustment in subsequent treatment fractions based on the irradiation angle of the initial treatment fraction;

[0089] The angle adjustment unit introduces new angle combinations in subsequent treatment fractions by rotating the gantry or adjusting the irradiation angle to supplement the tumor area not covered in the initial fractions and further reduce the radiation exposure to normal tissues. These new irradiation angles can be selected by a heuristic algorithm, aiming to cover key angles not included in the initial fractions, thereby ensuring comprehensive coverage of the tumor. The rotation angle of each treatment fraction is determined based on the principle of optimizing the remaining irradiation angles, minimizing radiation exposure to organs at risk (OARs), thereby enhancing the compliance of the overall dose distribution and the treatment effect.

[0090] Example: In the second treatment fraction, the field angles are adjusted to 15°, 45°, 75°, 135°, and 165° to cover the tumor area that was not fully covered in the previous fraction and to reduce the dose exposure to the heart and spinal cord.

[0091] Furthermore, for example, the previously mentioned solution may be adopted. Specifically:

[0092] At this time, in the irradiation angle selection of the initial treatment fraction, a single irradiation head uses N irradiation angles A1-AN (generally 4≤N≤9) for multiple irradiations. The angle adjustment unit uses the adaptive simulated annealing method (ASA) to calculate the following objective function values ​​for the number of irradiations of the irradiation head and the irradiation angle during each irradiation:

[0093] minf(β)

[0094] in,

[0095] Moreover, β is the angle of the frame relative to the area to be irradiated during rotation, M is the number of heads (for example, 3≤M≤5), L is the number of rotations of the heads, and B is the angle of the irradiation direction of the heads in each rotation relative to the frame.

[0096] It can be seen that the value of β should minimize the above formula.

[0097] A monitoring and adjustment unit 103 is used to perform dose accumulation, monitoring and adjustment based on the irradiation angle of the initial treatment fraction and the adjusted angle in the subsequent treatment fractions;

[0098] The monitoring and adjustment unit monitors the dose distribution of each fraction in real time throughout the treatment process, and accumulates the total radiation dose to the tumor and critical organs. The key to cumulative dose monitoring is to convert the dose delivered by each treatment fraction into an equivalent 2Gy fractional dose EQD2, so that accurate dose integration can be performed between all treatment fractions. The EQD2 model provides a standardized indicator to compare different treatment plans by adjusting the physical dose and taking into account the differences between fractions, thereby ensuring the safety and effectiveness of the treatment. The EQD2 conversion formula is as follows:

[0099]

[0100] Where D represents the total dose (Gy), d is the fractional dose in each treatment fraction (Gy), and α / β is a parameter for a specific tissue or tumor that represents the radiobiological response characteristics of the tissue. For tumors, typical α / β values ​​are usually around 10 Gy, while for normal tissues, especially those with late responses, α / β values ​​are usually between 2 and 4 Gy.

[0101] After calculating the EQD2 for each treatment fraction, the monitoring and adjustment unit adds these values ​​to obtain the total EQD2 for the entire treatment process. This cumulative EQD2 is then compared with the clinical prescription requirements to ensure that the combined dose of all treatment fractions meets the treatment goals while avoiding exceeding the safety threshold of critical organs.

[0102] If the cumulative dose of critical organs is found to be close to or exceeds the safety threshold during treatment, the radiation therapy physicist can adjust the irradiation angle and plan of subsequent fractions based on the dose accumulation data to ensure the safety and efficacy of the treatment process.

[0103] Example: During the third treatment fraction, the radiation physicist noticed that the dose accumulation of the spinal cord was close to the safety threshold and decided to adjust the radiation field angle to 20°, 60°, 100°, 140° and 180° to reduce further radiation exposure to the spinal cord and enhance coverage of the tumor margin. This adjustment ensures that the radiation exposure of the spinal cord is controlled within a safe range while still effectively covering the tumor area.

[0104] Evaluation unit 104: used to perform dose evaluation after treatment is completed.

[0105] After all treatment fractions are completed, the entire treatment process is comprehensively evaluated to analyze the dose coverage of the tumor and the protection of key organs. Through comprehensive analysis of the cumulative dose, it is ensured that the treatment has achieved the expected effect, and based on these data, it provides a reference for the treatment plan of similar cases in the future and further optimizes the radiotherapy plan.

[0106] Example: After a lung cancer patient completes a full treatment cycle, the radiotherapy team evaluates the total dose distribution and confirms that the tumor area is adequately covered while the radiation doses to the heart and spinal cord remain within a safe range.

[0107] This method is not only applicable to modern advanced FLASH accelerators, but also to traditional accelerator equipment with relatively backward technology. For equipment that cannot perform gantry rotation or multi-angle radiation field combination, by adjusting the irradiation angle between different fractions, the effect of multi-angle coverage can also be achieved to ensure effective treatment of complex tumors.

[0108] When performing treatment on a traditional accelerator, since the device cannot rotate the gantry, angle adjustment between fractions becomes the key to optimizing the treatment effect. In each treatment fraction, the device irradiates at a fixed field angle, but after each treatment, the irradiation angle of the next fraction is recalculated and adjusted, thereby gradually achieving multi-angle coverage and achieving the ideal treatment effect.

[0109] It should be noted that the radiotherapy device for adjusting the angle between treatment fractions during multi-fraction radiotherapy according to the present invention is preferably suitable for FLASH equipment, but the present invention can be applied to any suitable radiotherapy device; FLASH equipment is only a preferred example.

[0110] It should be noted that, unless otherwise specified, the terms "first", "second", "third", etc. in the specification are only used to distinguish the various components, elements, steps, etc. in the specification, and are not used to indicate the logical relationship or sequential relationship between the various components, elements, steps, etc.

[0111] It is to be understood that, although the present invention has been disclosed as a preferred embodiment, the above embodiment is not intended to limit the present invention. For any person skilled in the art, without departing from the scope of the technical solution of the present invention, the technical content disclosed above can be used to make many possible changes and modifications to the technical solution of the present invention, or modified into equivalent embodiments of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of protection of the technical solution of the present invention.

Claims

1. A radiotherapy device for adjusting the angle between treatment fractions during multi-fraction radiotherapy, the device comprising: Angle selection unit: used to select the irradiation angle for the initial treatment fractions; Angle adjustment unit: used to perform angle adjustment in subsequent treatment fractions based on the irradiation angle of the initial treatment fraction; Monitoring and adjustment unit: used to perform dose accumulation, monitoring and adjustment based on the irradiation angle of the initial treatment fraction and the adjusted angle in the subsequent treatment fractions.

2. The radiotherapy device for adjusting the angle between treatment fractions during multi-fraction radiotherapy according to claim 1, wherein the angle adjustment unit comprises a data input unit and a control unit; the data input unit is used to input the IMRT treatment plan big data using a single irradiation head; the control unit retrieves the IMRT plan actual of the case closest to the object to be treated from the IMRT treatment plan big data according to the object to be treated, and optimizes based on the retrieved IMRT plan actual to determine the number of irradiation cycles of the irradiation head and the irradiation angle during each irradiation cycle.

3. The radiotherapy device for adjusting the angle between treatment fractions during multi-fraction radiotherapy according to claim 2, wherein the control unit is configured to perform the following steps: In the retrieved IMRT plan, a single irradiation head uses N irradiation angles A1-AN for multiple irradiations. The control unit uses an adaptive simulated annealing method to calculate the following objective function values ​​for the number of irradiations of the irradiation head and the irradiation angle during each irradiation: min f(β) in, β is the angle of the frame relative to the area to be irradiated during the round irradiation, M is the number of heads, L is the number of round irradiations of the heads, and B is the angle of the irradiation direction of the heads in each round irradiation relative to the frame.

4. The radiotherapy device for adjusting the angle between treatment fractions during multi-fraction radiotherapy according to claim 3, characterized in that: The number of machine heads is between 3 and 5.

5. The radiotherapy device for adjusting the angle between treatment fractions during multi-fraction radiotherapy according to claim 3, characterized in that: The number of times the nose is illuminated is between 1 and 4 times.

6. The radiotherapy device for adjusting the angle between treatment fractions during multi-fraction radiotherapy according to claim 1, characterized in that: IMRT treatment plan big data refers to case big data related to the hospital's IMRT treatment plan.

7. The radiotherapy device for adjusting the angle between treatment fractions during multi-fraction radiotherapy according to claim 1, characterized in that: After rotational irradiation, the fractionated doses at different gantry angles and the final synthesized total dose of the target area all meet the prescribed dose requirements.

8. The radiotherapy device for adjusting the angle between treatment fractions during multi-fraction radiotherapy according to claim 1, characterized in that: The angle adjustment unit introduces new angle combinations in subsequent treatment fractions by rotating the gantry or adjusting the irradiation angle to supplement the tumor area not covered in the initial fractions and further reduce the radiation exposure to normal tissues.

9. The radiotherapy device for adjusting the angle between treatment fractions during multi-fraction radiotherapy according to claim 1, characterized in that: The monitoring and adjustment unit monitors the dose distribution of each fraction in real time during the entire treatment process, and cumulatively calculates the total radiation dose to the tumor and key organs; the dose delivered in each treatment fraction is converted into an equivalent 2Gy fractional dose EQD2: Where D represents the total dose (Gy), d is the fractional dose in each treatment fraction (Gy), and α / β is a parameter for a specific tissue or tumor that represents the radiobiological response characteristics of the tissue; for tumors, typical α / β values ​​are usually around 10 Gy, while for normal tissues, especially those with late responses, α / β values ​​are usually between 2 and 4 Gy; Furthermore, after calculating the EQD2 for each treatment fraction, the monitoring and adjustment unit adds up these values ​​to obtain the total EQD2 for the entire treatment process, and then compares this cumulative EQD2 with the clinical prescription requirements to ensure that the combined dose of all treatment fractions meets the treatment goals.

10. The radiotherapy device for adjusting the angle between treatment fractions during multi-fraction radiotherapy according to any one of claims 1 to 3, characterized in that It also includes: Evaluation unit: used to perform dose evaluation after the end of treatment, conduct a comprehensive evaluation of the entire treatment process after all treatment fractions are completed, analyze the dose coverage of the tumor and the protection of key organs, and ensure that the treatment has achieved the expected results through comprehensive analysis of the cumulative dose. Based on these data, it provides reference for treatment plans for similar cases in the future and further optimizes the radiotherapy plan.

11. The radiotherapy device for adjusting the angle between treatment fractions during multi-fraction radiotherapy according to any one of claims 1 to 3, characterized in that: The radiotherapy device used for adjusting the angle between treatment fractions during multi-fraction radiotherapy is a FLASH device.

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