Lattice space segmentation radiotherapy method based on adaptive precise dose superposition model

Abstract

The invention discloses a lattice space segmentation radiotherapy method based on an adaptive precise dose superposition model, and relates to the technical field of radiotherapy. The SRS and the VMAT are fused, a dose superposition treatment scheme is provided, so that the SRS provides an accurate high peak dose in a target area, the VMAT supplements and delivers a proper valley dose, an optimized space dose grid mode is formed, the peak-valley dose ratio is optimized in real time, treatment parameters are dynamically adjusted according to individual characteristics of a patient, the optimization of the treatment effect is ensured, and the treatment effect is improved. According to the invention, submillimeter-level spatial positioning precision and high-precision dose delivery control can be realized, the spatial selectivity of treatment is further improved, the biological effect of radiotherapy is remarkably enhanced, and meanwhile, surrounding normal tissues are protected to the greatest extent.

Description

Technical Field

[0001] The present invention relates to the field of radiotherapy technology, and in particular to a lattice space segmentation radiotherapy method based on an adaptive precise dose superposition model. Background Art

[0002] Lattice radiation therapy (LRT) is an innovative spatially fractionated radiotherapy technique that has received widespread clinical attention in recent years. LRT can significantly improve local control rates and reduce toxic reactions to normal tissues by constructing alternating high and low dose areas (i.e., peak and trough dose areas) inside the tumor. LRT has significant advantages in theory, which are mainly achieved through two technologies: volume-modulated arc therapy (VMAT) and stereotactic radiosurgery (SRS). Compared with VMAT, SRS can achieve a higher peak-to-trough ratio in the tumor target area and a larger dose gradient. Regardless of the large volume and long treatment time, the advantages of SRS peak-to-trough dose characteristics provide a better choice for clinical treatment. Although VMAT and SRS can meet clinical time requirements in LRT treatment of small tumors, for LRT treatment of large tumors, the treatment time of SRS is significantly prolonged, which may exceed 60 minutes, affecting the patient's tolerance. It is difficult for patients to remain still for a long time during treatment, which increases discomfort and treatment tolerance. In this case, a combined irradiation strategy of SRS and VMAT can be selected, with peak dose delivery completed by SRS and trough dose supplemented by VMAT.

[0003] However, the combined irradiation strategy of SRS and VMAT has certain limitations. First, there is a lack of systematic comparison, and it is impossible to achieve the best combination of the two, thereby failing to maximize the local control rate of tumors and reduce normal tissue damage. Second, the technical coordination is poor. The differences between VMAT and SRS in dose delivery methods, treatment processes, and time efficiency may lead to the need for higher technical coordination and complex treatment plan design during combined treatment, which cannot ensure the efficiency and safety of treatment, while avoiding problems such as redundant treatment or uneven dose distribution. Summary of the invention

[0004] The purpose of the present invention is to provide a lattice space fractionation radiotherapy method based on an adaptive precise dose superposition model to improve the above technical problems.

[0005] In order to achieve the above-mentioned object of the invention, the embodiment of the present invention provides the following technical solutions:

[0006] A lattice space fractionation radiotherapy method based on an adaptive precise dose superposition model includes:

[0007] S1, scanning the patient's lesion position and obtaining the corresponding CT image data;

[0008] S2. Based on the CT image data, draw the corresponding M lattice target areas to obtain the corresponding tumor volume;

[0009] S3. Develop LRT lattice radiotherapy plan;

[0010] S4. Establish an adaptive and precise dose superposition model;

[0011] S5. Based on the LRT lattice radiotherapy plan, patients are given lattice space-fractionated radiotherapy through an adaptive precise dose superposition model.

[0012] Further, the S2 comprises the following steps:

[0013] S2-1, based on the CT image data, drawing the corresponding tumor target area and organ-at-risk area;

[0014] S2-2, based on the delineation rules, the tumor target area and the organ at risk area are delineated using automatic delineation software and a hexagonal closest packing digital model to obtain M lattice target areas;

[0015] S2-3. Calculate the patient's tumor volume based on each of the lattice target areas.

[0016] Further, the LRT lattice radiotherapy scheme includes an SRS treatment scheme and a VMAT treatment scheme;

[0017] The S3 comprises the following steps:

[0018] S3-1, determining the number of VMAT arcs based on the number M of the lattice target areas and the VMAT arc selection rule;

[0019] S3-2, using the Monaco planning system to select an accelerator, set the corresponding multi-leaf collimator isocenter width, ray energy, accelerator dose rate, handpiece speed, and beam intensity, and obtain the VMAT treatment plan;

[0020] S3-3. Use the Multi Plan V3.5 planning system to select a collimator, and set the corresponding radiation energy, collimator size and irradiation angle to obtain the SRS treatment plan.

[0021] Furthermore, the adaptive precise dose superposition model includes an SRS spatial dose distribution model, a VMAT spatial dose compensation model and a total dose spatial distribution model;

[0022] The S4 comprises the following steps:

[0023] S4-1, based on the tumor volume, setting an initial value of the peak contribution ratio; based on each of the lattice target areas, acquiring a corresponding initial spatial dose distribution map;

[0024] S4-2, based on the initial spatial dose distribution map, obtaining corresponding spatial dose distribution characteristics;

[0025] S4-3, constructing the SRS spatial dose distribution model using a Gaussian peak superposition model based on the spatial dose distribution characteristics;

[0026] S4-4, based on the spatial dose distribution characteristics, constructing the VMAT spatial dose compensation model using an optimized spatial rectangular function;

[0027] S4-5. Based on the SRS spatial dose distribution model, the VMAT spatial dose compensation model and the spatial dose boundary constraint condition, the total dose spatial distribution model is obtained.

[0028] Furthermore, the formula of the SRS spatial dose distribution model is:

[0029] ;

[0030] in, Indicates at the current moment The spatial position of the lattice target area The peak dose at represents the basic peak dose, represents the peak contribution ratio, represents the total peak dose, represents the summation function, Indicates The peak position, represents the standard deviation of the Gaussian distribution, represents an exponential function with the natural constant e as the base, Indicates at the current moment The spatial position of the lattice target area Dose delivery rate at

[0031] The formula of the VMAT spatial dose compensation model is:

[0032] ;

[0033] in, represents the optimized spatial rectangular function, Indicates at the current moment The spatial position of the lattice target area The valley dose at represents the basal trough dose;

[0034] The formula of the total dose spatial distribution model is:

[0035] ;

[0036] in, Indicates at the current moment The spatial position of the lattice target area The total dose.

[0037] Furthermore, the spatial dose boundary constraint conditions include peak value constraint, valley value constraint, valley value superposition condition and peak value superposition condition;

[0038] The peak constraint is:

[0039] ;

[0040] The valley constraint:

[0041] ;

[0042] The valley value superposition condition is:

[0043] ;

[0044] The peak superposition condition is:

[0045] ;

[0046] in, , Respectively represent the maximum value, represents the peak total dose, Indicates dosage unit, Indicates the total trough dose.

[0047] Further, the S5 comprises the following steps:

[0048] S5-1. Set treatment time threshold and dosage threshold;

[0049] S5-2, determining an initial value of the dose contribution ratio based on the initial value of the peak contribution ratio;

[0050] S5-3, based on the SRS treatment plan, the VMAT treatment plan and the initial value of the dose contribution ratio, respectively, the SRS spatial dose distribution model and the VMAT spatial dose compensation model are used to sequentially perform SRS treatment and VMAT treatment on the lattice target area of ​​the patient, and the treatment is monitored to obtain a monitoring treatment time;

[0051] S5-4, calculating the corresponding cumulative spatial dose value; obtaining the spatial dose distribution diagram of the current state through the total dose spatial distribution model;

[0052] S5-5, determine whether the cumulative spatial dose value exceeds the dose threshold; if so, end the lattice space fractionation radiotherapy; otherwise, enter S5-6;

[0053] S5-6, judging whether the monitoring treatment time exceeds the treatment time threshold; if so, proceeding to S5-7; otherwise, returning to S5-3;

[0054] S5-7. Based on the spatial dose distribution diagram of the current state, update the peak contribution ratio and return to S5-3.

[0055] Furthermore, the S5-3 comprises the following steps:

[0056] S5-3-1, based on the SRS treatment plan and the initial value of the dose contribution ratio, determine the peak dose through the SRS spatial dose distribution model;

[0057] S5-3-2, based on the peak dose, performing SRS treatment and monitoring on the lattice target area of ​​the patient;

[0058] S5-3-3, based on the VMAT treatment plan and the initial value of the dose contribution ratio, determining the valley dose by using the VMAT spatial dose compensation model;

[0059] S5-3-4. Based on the trough dose, VMAT treatment and monitoring are performed on the patient's lattice target area to obtain a corresponding monitoring treatment time.

[0060] Further, the S5-7 comprises the following steps:

[0061] S5-7-1, updating the dose contribution ratio according to the monitored treatment time to obtain an updated dose contribution ratio;

[0062] S5-7-2, judging whether the dose contribution ratio after the one-time update satisfies the dose constraint condition; if so, taking the dose contribution ratio after the one-time update as the dose contribution ratio of the current state; otherwise, taking the dose contribution ratio as the dose contribution ratio of the current state; and proceeding to S5-7-3;

[0063] S5-7-3, perform uniformity evaluation on the current spatial dose distribution diagram to obtain the corresponding uniformity evaluation result;

[0064] S5-7-4. Based on the uniformity evaluation result and the patient's tolerance, dynamically fine-tune the dose contribution ratio of the current state to obtain a corresponding fine-tuned dose contribution ratio;

[0065] S5-7-5. Based on the fine-tuned dose contribution ratio, update the peak contribution ratio and return to S5-3.

[0066] The beneficial effects of the present invention are:

[0067] The present invention integrates SRS and VMAT and proposes a dose superposition treatment scheme, so that SRS can provide accurate high peak doses in the target area, while VMAT can supplement and deliver an appropriate amount of valley doses, forming an optimized spatial dose grid pattern. It can optimize the peak-to-valley dose ratio in real time, dynamically adjust treatment parameters according to individual patient characteristics, ensure optimal treatment effects, achieve submillimeter spatial positioning accuracy and high-precision dose delivery control, further improve the spatial selectivity of treatment, and significantly enhance the biological effects of radiotherapy, while maximally protecting surrounding normal tissues. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0069] Figure 1 A flow chart of a method in an embodiment of the present invention;

[0070] FIG2 (a) is a dose distribution diagram corresponding to VMAT in an embodiment of the present invention;

[0071] FIG2( b ) is a dose distribution curve diagram corresponding to VMAT in an embodiment of the present invention;

[0072] FIG3 (a) is a dose distribution diagram corresponding to SRS in an embodiment of the present invention;

[0073] FIG3( b ) is a dose distribution curve diagram corresponding to SRS in an embodiment of the present invention;

[0074] Figure 4 This is a dose distribution curve diagram of an embodiment of the present invention in which the peak dose contribution ratio is 50%;

[0075] Figure 5 This is a dose distribution curve diagram of an embodiment of the present invention in which the peak dose contribution ratio is 70%;

[0076] FIG6 (a) is a peak dose distribution diagram before SRS treatment scheme fusion in an embodiment of the present invention;

[0077] FIG6 ( b ) is a peak dose distribution curve diagram before SRS treatment scheme fusion in an embodiment of the present invention;

[0078] FIG. 7 ( a ) is a trough dose distribution diagram of the VMAT treatment scheme before fusion in an embodiment of the present invention;

[0079] FIG7( b ) is a trough dose distribution curve diagram of the VMAT treatment scheme before fusion in an embodiment of the present invention;

[0080] FIG8 (a) is a peak dose distribution diagram of the SRS-VMAT treatment scheme in an embodiment of the present invention;

[0081] FIG8( b ) is a peak dose distribution curve diagram of the SRS-VMAT treatment scheme in an embodiment of the present invention;

[0082] Fig. 9 It is a monitoring treatment time curve diagram before and after fusion in an embodiment of the present invention. DETAILED DESCRIPTION

[0083] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present invention.

[0084] See also Figure 1 This embodiment provides a lattice space fractionation radiotherapy method based on an adaptive precise dose superposition model, which includes:

[0085] S1, scanning the patient's lesion position and obtaining the corresponding CT image data;

[0086] The patient was scanned using Philips 16-slice BrillianceTM CT BigBore large-aperture CT simulation positioning device. The patient was in a supine position and fixed with a head, neck, and shoulder thermoplastic film mold. The scanning range and layer thickness of the large-aperture CT simulation positioning device were set from the top of the skull to the upper edge of the sternum and 1 mm, respectively.

[0087] S2. Based on the CT image data, draw the corresponding M lattice target areas to obtain the corresponding tumor volume;

[0088] The S2 comprises the following steps:

[0089] S2-1, based on the CT image data, drawing the corresponding tumor target area and organ-at-risk area;

[0090] S2-2, based on the delineation rules, the tumor target area and the organ at risk area are delineated using automatic delineation software and a hexagonal closest packing digital model to obtain M lattice target areas;

[0091] S2-3. Calculate the patient's tumor volume based on each of the lattice target areas.

[0092] The delineation rules are:

[0093] (1) Outlining within the tumor target volume (GTV) while avoiding the tumor target volume and vessels in the organ-at-risk region;

[0094] (2) The distance between the edge of the tumor target volume (GTV) and the edge of the lattice target volume (GTV-Lattice) is not less than 1 cm;

[0095] (3) The volume ratio of the tumor target volume (GTV) to the lattice target volume (GTV-Lattice) is within the scope of

[0096] (4) The initial arrangement of the lattice corresponding to the lattice target region (GTV-Lattice) is hexagonal close packing (HCP), and the single-layer arrangement of the lattice follows the planar hexagonal symmetry, that is:

[0097] ;

[0098] The distribution volume of the lattice target region (GTV-Lattice) is:

[0099] ;

[0100] in, , , denote column index, row index and layer index respectively, , , Respectively represent the distances between the centers of two adjacent spheres in the x-axis, y-axis, and z-axis directions. Indicates Layer Column and The position vector of the center of the sphere of the row, represents a constant, represents the absolute value, represents the number of spheres corresponding to the lattice target area, Represents the radius of the sphere.

[0101] S3. Develop LRT lattice radiotherapy plan;

[0102] The LRT lattice radiotherapy plan includes the SRS treatment plan and the VMAT treatment plan; the SRS treatment plan and the VMAT treatment plan use the same prescription dose, the 90% volume irradiation dose (D90) of the tumor target area (GTV) is not less than 4Gy / time, and the 90% volume irradiation dose (D90) of the lattice target area (GTV-Lattice) is not less than 12Gy / time.

[0103] The S3 comprises the following steps:

[0104] S3-1. Determine the number of VMAT arcs based on the number M of the lattice target regions and the VMAT arc selection rule; the VMAT arc selection rule is:

[0105] When the number of lattice target regions M is less than 10, the number of VMAT arcs is set to 2 to 3; when the number of lattice target regions M is greater than or equal to 10, the number of VMAT arcs is set to 4;

[0106] S3-2. Use the Monaco planning system to select an accelerator, set the corresponding multi-leaf collimator isocenter width, ray energy, accelerator dose rate, handpiece speed, and beam intensity, and obtain the VMAT treatment plan; for example, the accelerator selects the Elekta Infinity accelerator, the multi-leaf collimator isocenter width is 5 mm, the ray energy selects the 6MVX-ray non-uniform mode, and the accelerator dose rate is 1400MU / min. MU represents the dose unit.

[0107] S3-3. The CyberKnife M6TM model was selected using the Multi Plan V3.5 planning system, and a 5 to 10 mm variable (Iris) collimator was used for dose optimization, and the corresponding radiation energy, collimator size and irradiation angle were set to obtain the SRS treatment plan. The variable (Iris) collimator uses a series of tungsten blocks to form a set of 12-sided variable shapes, so that the collimator size can be flexibly adjusted in a single treatment path to achieve a variety of combined configurations.

[0108] S4. Establish an adaptive and precise dose superposition model;

[0109] The adaptive precise dose superposition model includes an SRS spatial dose distribution model, a VMAT spatial dose compensation model and a total dose spatial distribution model;

[0110] The S4 comprises the following steps:

[0111] S4-1. Setting the peak contribution ratio based on the tumor volume Based on each of the lattice target areas, obtaining a corresponding initial spatial dose distribution map;

[0112] S4-2, based on the initial spatial dose distribution map, obtaining corresponding spatial dose distribution characteristics;

[0113] S4-3, constructing the SRS spatial dose distribution model using a Gaussian peak superposition model based on the spatial dose distribution characteristics;

[0114] The formula of the SRS spatial dose distribution model is:

[0115] ;

[0116] in, Indicates at the current moment The spatial position of the lattice target volume (lattice point within the tumor target volume GTV) The peak dose at represents the basic peak dose, represents the peak contribution ratio, represents the total peak dose, represents the summation function, Indicates The peak position, represents the standard deviation of the Gaussian distribution, represents an exponential function with the natural constant e as the base, Indicates at the current moment The spatial position of the lattice target area Dose delivery rate at peak position ( , , ) are 20mm, 40mm and 60mm respectively.

[0117] The Gaussian peak superposition model is used to construct the SRS spatial dose distribution model, which is conducive to accurately controlling the peak width, and then effectively controlling the SRS dose delivery to the tumor area, achieving precise treatment for different patients.

[0118] S4-4, based on the spatial dose distribution characteristics, constructing the VMAT spatial dose compensation model using an optimized spatial rectangular function;

[0119] The formula of the VMAT spatial dose compensation model is:

[0120] ;

[0121] in, represents the optimized spatial rectangular function, Indicates at the current moment The spatial position of the lattice target volume (lattice point within the tumor target volume GTV) The valley dose at represents the basal trough dose;

[0122] Optimized spatial rectangular function for:

[0123] ;

[0124] S4-5. Based on the SRS spatial dose distribution model, the VMAT spatial dose compensation model and the spatial dose boundary constraint condition, the total dose spatial distribution model is obtained.

[0125] The formula of the total dose spatial distribution model is:

[0126] ;

[0127] in, Indicates at the current moment The spatial position of the lattice target volume (lattice point within the tumor target volume GTV) The total dose.

[0128] The spatial dose boundary constraint conditions include peak value constraint, valley value constraint, valley value superposition condition and peak value superposition condition;

[0129] The peak constraint is:

[0130] ;

[0131] The valley constraint:

[0132] ;

[0133] The valley value superposition condition is:

[0134] ;

[0135] The peak superposition condition is:

[0136] ;

[0137] in, , Respectively represent the maximum value, represents the peak total dose, Indicates dosage unit, Indicates the total trough dose.

[0138] S5. Based on the LRT lattice radiotherapy plan, patients are given lattice space-fractionated radiotherapy through an adaptive precise dose superposition model.

[0139] The S5 comprises the following steps:

[0140] S5-1. Set the treatment time threshold and dosage threshold; the time threshold can be set to 50 minutes, and the dosage threshold can be set according to different patients.

[0141] S5-2, based on the peak contribution ratio The initial value of The initial value of , the corresponding formula is:

[0142] ;

[0143] S5-3, based on the SRS treatment plan, the VMAT treatment plan and the initial value of the dose contribution ratio, respectively, the SRS spatial dose distribution model and the VMAT spatial dose compensation model are used to sequentially perform SRS treatment and VMAT treatment on the lattice target area of ​​the patient, and the treatment is monitored to obtain a monitoring treatment time;

[0144] The S5-3 comprises the following steps:

[0145] S5-3-1, based on the SRS treatment plan and the initial value of the dose contribution ratio, determine the peak dose through the SRS spatial dose distribution model;

[0146] S5-3-2. Based on the peak dose, the patient's lattice target area is treated with SRS and monitored; the SRS treatment is CK-6D (six-dimensional skull tracking) technology.

[0147] S5-3-3. Based on the VMAT treatment plan, the dose contribution ratio The initial value of is determined by the VMAT spatial dose compensation model;

[0148] S5-3-4. Based on the trough dose, VMAT treatment and monitoring are performed on the patient's lattice target area to obtain a corresponding monitoring treatment time.

[0149] S5-4, calculating the corresponding cumulative spatial dose value; obtaining the spatial dose distribution diagram of the current state through the total dose spatial distribution model;

[0150] Cumulative space dose value The corresponding formula is:

[0151] ;

[0152] in, Indicates monitoring treatment time, Represents integral.

[0153] S5-5, determine whether the cumulative spatial dose value exceeds the dose threshold; if so, end the lattice space fractionation radiotherapy; otherwise, enter S5-6;

[0154] S5-6, judging whether the monitoring treatment time exceeds the treatment time threshold; if so, proceeding to S5-7; otherwise, returning to S5-3;

[0155] S5-7. Based on the spatial dose distribution diagram of the current state, update the peak contribution ratio and return to S5-3.

[0156] The S5-7 comprises the following steps:

[0157] S5-7-1. Update the dose contribution ratio according to the monitoring treatment time , and get the updated dose contribution ratio. The corresponding formula is:

[0158] ;

[0159] S5-7-2, determine whether the dose contribution ratio after the one-time update meets the dose constraint condition; if so, use the dose contribution ratio after the one-time update as the dose contribution ratio of the current state; otherwise, use the dose contribution ratio as the dose contribution ratio of the current state; enter S5-7-3; wherein the dose constraint condition is:

[0160] .

[0161] S5-7-3. Evaluate the uniformity of the current spatial dose distribution map, that is, calculate the maximum dose D in the target area corresponding to the current spatial dose distribution map. max and minimum dose D min , further calculate the corresponding dose uniformity index (HI), evaluate the dose coverage in the target volume corresponding to the spatial dose distribution diagram of the current state, draw the corresponding dose volume histogram (DVH) and analyze it, determine the corresponding key parameters, and obtain the evaluation uniformity results; the evaluation uniformity results include HI value, coverage rate and key parameters.

[0162] S5-7-4. Based on the evaluation uniformity results and the patient's tolerance, with the goal of maintaining the total dose constraint (peak value 12Gy, valley value 4Gy) unchanged, the dose contribution ratio of the current state is dynamically fine-tuned to obtain the corresponding fine-tuned dose contribution ratio; in this process, a progressive strategy is adopted, using the preset value range in the initial stage to ensure the safety of the patient during the dynamic fine-tuning process, and then expanding the value range to obtain a larger optimization space to further improve the accuracy of dose delivery. The preset value range is , the expanded value range is .in, Indicates the dose contribution ratio of the current status.

[0163] The expanded range of values ​​can provide a larger space for dose optimization, but it is necessary to ensure that the adjusted total dose still meets the requirements (peak value 12Gy, trough value 4Gy), which maintains the flexibility of adjustment and ensures the safety of treatment.

[0164] S5-7-5. Based on the fine-tuned dose contribution ratio, the peak contribution ratio is updated using the same formula as S5-2. And return to S5-3.

[0165] Updating the peak contribution ratio In the process of evaluating the uniformity results, the dose contribution ratio is taken as an important factor, so as to evaluate the uniformity results and the peak contribution ratio. and dose contribution ratio The mapping relationship between ) Contribution ratio to peak value Adjust to form a complete feedback control loop to effectively control the contribution ratio to the peak value The adjustment range can prevent the dose distribution from exceeding the dose constraint, reducing the treatment safety and damaging the normal tissue around the endangered organ area.

[0166] In addition, the peak contribution ratio As a spatially adaptive parameter, it affects the dose of VMAT and SRS during treatment, namely:

[0167] (1) SRS peak dose control: ;in, represents the peak SRS dose.

[0168] (2) VMAT peak dose control: ;in, represents the VMAT peak dose.

[0169] (3) Total trough dose control: is 4Gy.

[0170] Thus, when updating the peak contribution ratio In the process, the SRS spatial dose distribution model, VMAT spatial dose compensation model and total dose spatial distribution model are updated as follows:

[0171] ;

[0172] ;

[0173] ;

[0174] in, , , Respectively represent the current time after update The spatial position of the lattice target volume (lattice point within the tumor target volume GTV) The peak dose at the current time The spatial position of the lattice target volume (lattice point within the tumor target volume GTV) The valley dose at the current time The spatial position of the lattice target volume (lattice point within the tumor target volume GTV) The total dose.

[0175] During the entire treatment process, the peak dose was controlled within the range of 12Gy±0.5Gy, the trough dose was controlled within the range of 4Gy±0.2Gy, and the total treatment time was less than 50 minutes.

[0176] The present invention acquires the spatial dose distribution in real time and performs uniformity evaluation, adjusts the dose contribution ratio in real time based on the uniformity evaluation results and monitoring the treatment time, and further dynamically adjusts the peak contribution ratio, thereby achieving precise control of SRS and VMAT in the spatial dose distribution and ensuring the high efficiency and safety of the treatment.

[0177] The experiment was conducted on the data of patients with well-differentiated squamous cell carcinoma of the left paranasal sinus. The initial value of the dose contribution ratio was set to 0.67, and the treatment time threshold was 50 minutes.

[0178] By processing the CT image data of the patient, the present invention formulates the corresponding LRT lattice radiotherapy plan for the patient, as shown in Figure 2 (a), Figure 2 (b), Figure 3 (a) and Figure 3 (b), and obtains the corresponding VMAT treatment plan and SRS treatment plan. The X-axis of Figure 2 (b) and Figure 3 (b) is the distance (mm), and the Y-axis is the relative value of the dose distribution; the relative value of the dose distribution is used to evaluate the dose uniformity and coverage, and to describe the relative intensity of the dose distribution, that is, to describe the radiotherapy profile and to evaluate the plan.

[0179] The VMAT treatment plan and SRS treatment plan are implemented for patients using the adaptive precise dose superposition model. During the treatment process, the peak dose contribution ratio is adjusted in real time. When the peak dose contribution ratio is 50% of the initial value of the peak dose contribution ratio, the dose distribution curve in the tumor target volume (GTV) is as follows Figure 4 When the peak dose contribution ratio is 70% of the initial value of the peak dose contribution ratio, the dose distribution curve in the tumor target volume (GTV) is as shown in Figure 5 shown.

[0180] The peak dose of the SRS treatment plan was verified using the American Accuray Multi Plan V3.5 system. The corresponding verification results are shown in Figure 6 (a) and Figure 6 (b), which respectively show the pure peak dose spatial distribution contributed by the SRS treatment plan and the peak dose distribution curve at a fixed measurement point in the tumor target volume (GTV) area, which are consistent with the theoretical expected spatial dose distribution characteristics.

[0181] The Monaco planning system was used to verify the trough dose of the VMAT treatment plan. The corresponding verification results are shown in Figure 7 (a) and Figure 7 (b), which respectively show the spatial distribution of the pure trough dose contributed by the VMAT treatment plan and the trough dose distribution curve at a fixed measurement point in the tumor target volume (GTV) area. The spatial distribution of the pure trough dose is uniform and the curve is flat, further demonstrating the advantage of VMAT in trough dose delivery.

[0182] The VMAT treatment plan and the SRS treatment plan were implemented by using the method of the present invention (SAPDS-SFRT, a fusion strategy method of VMAT treatment plan and SRS treatment plan). The corresponding dose distribution diagram, dose distribution curve diagram and monitoring treatment time comparison diagram are shown in Figures 8(a), 8(b) and Fig. 9 As shown. Compared with the use of VMAT treatment plan and SRS treatment plan alone, the dose of SAPDS-SFRT is more accurate, and the precise superposition of peak and valley doses is achieved. While ensuring the quality of treatment, the goal of optimizing treatment efficiency is achieved; the treatment time of SAPDS-SFRT is significantly reduced compared with the treatment time of VMAT treatment plan and SRS treatment plan, which is within the clinically acceptable range, further proving that the present invention can achieve precise treatment of different patients in a short time, reduce treatment time, and reduce damage to the patient's normal tissues. In Figure 8 (b), the purple curve is the dose distribution curve of the VMAT treatment plan, the blue curve is the dose distribution curve of the SRS treatment plan, and the yellow curve is the dose distribution curve of SAPDS-SFRT. Fig. 9 In the figure, the orange curve is the monitoring treatment time curve of the SRS treatment plan, the yellow curve is the monitoring treatment time curve of the VMAT treatment plan, and the purple curve is the monitoring treatment time curve of SAPDS-SFRT. The X-axis of Figure 6 (b), Figure 7 (b), and Figure 8 (b) is the distance (mm), and the Y-axis is the relative value of the dose distribution.

[0183] In summary, the present invention integrates SRS and VMAT and proposes a dose superposition treatment scheme, so that SRS can provide accurate high peak doses in the target area, while VMAT can supplement and deliver an appropriate amount of valley doses, forming an optimized spatial dose grid pattern. It can optimize the peak-to-valley dose ratio in real time, dynamically adjust treatment parameters according to individual patient characteristics, ensure the optimization of treatment effects, achieve submillimeter spatial positioning accuracy and high-precision dose delivery control, further improve the spatial selectivity of treatment, and significantly enhance the biological effects of radiotherapy, while maximally protecting surrounding normal tissues.

[0184] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A lattice space fractionation radiotherapy method based on an adaptive precise dose superposition model, characterized in that: include: S1, scanning the patient's lesion position and obtaining the corresponding CT image data; S2. Based on the CT image data, draw the corresponding M lattice target areas to obtain the corresponding tumor volume; S3. Develop LRT lattice radiotherapy plan; S4. Establish an adaptive and precise dose superposition model; S5. Based on the LRT lattice radiotherapy plan, patients are given lattice space-fractionated radiotherapy through an adaptive precise dose superposition model.

2. The lattice space fractionation radiotherapy method based on the adaptive precise dose superposition model according to claim 1 is characterized in that: The S2 comprises the following steps: S2-1, based on the CT image data, drawing the corresponding tumor target area and organ-at-risk area; S2-2, based on the delineation rules, the tumor target area and the organ at risk area are delineated using automatic delineation software and a hexagonal closest packing digital model to obtain M lattice target areas; S2-3. Calculate the patient's tumor volume based on each of the lattice target areas.

3. The lattice space fractionation radiotherapy method based on the adaptive precise dose superposition model according to claim 1, characterized in that: The LRT lattice radiotherapy scheme includes an SRS treatment scheme and a VMAT treatment scheme; The S3 comprises the following steps: S3-1, determining the number of VMAT arcs based on the number M of the lattice target areas and the VMAT arc selection rule; S3-2, using the Monaco planning system to select an accelerator, set the corresponding multi-leaf collimator isocenter width, ray energy, accelerator dose rate, handpiece speed, and beam intensity, and obtain the VMAT treatment plan; S3-3. Use the Multi Plan V3.5 planning system to select a collimator, and set the corresponding radiation energy, collimator size and irradiation angle to obtain the SRS treatment plan.

4. The lattice space fractionation radiotherapy method based on the adaptive precise dose superposition model according to claim 1, characterized in that: The adaptive precise dose superposition model includes an SRS spatial dose distribution model, a VMAT spatial dose compensation model and a total dose spatial distribution model; The S4 comprises the following steps: S4-1, based on the tumor volume, setting an initial value of the peak contribution ratio; based on each of the lattice target areas, acquiring a corresponding initial spatial dose distribution map; S4-2, based on the initial spatial dose distribution map, obtaining corresponding spatial dose distribution characteristics; S4-3, constructing the SRS spatial dose distribution model using a Gaussian peak superposition model based on the spatial dose distribution characteristics; S4-4, based on the spatial dose distribution characteristics, constructing the VMAT spatial dose compensation model using an optimized spatial rectangular function; S4-5. Based on the SRS spatial dose distribution model, the VMAT spatial dose compensation model and the spatial dose boundary constraint condition, the total dose spatial distribution model is obtained.

5. The lattice space fractionation radiotherapy method based on the adaptive precise dose superposition model according to claim 4, characterized in that: The formula of the SRS spatial dose distribution model is: ； in, Indicates at the current moment The spatial position of the lattice target area The peak dose at represents the basic peak dose, represents the peak contribution ratio, represents the total peak dose, represents the summation function, Indicates The peak position, represents the standard deviation of the Gaussian distribution, represents an exponential function with the natural constant e as the base, Indicates at the current moment The spatial position of the lattice target area Dose delivery rate at The formula of the VMAT spatial dose compensation model is: ； in, represents the optimized spatial rectangular function, Indicates at the current moment The spatial position of the lattice target area The valley dose at represents the basal trough dose; The formula of the total dose spatial distribution model is: ； in, Indicates at the current moment The spatial position of the lattice target area The total dose.

6. The lattice space fractionation radiotherapy method based on the adaptive precise dose superposition model according to claim 5, characterized in that: The spatial dose boundary constraint conditions include peak value constraint, valley value constraint, valley value superposition condition and peak value superposition condition; The peak constraint is: ； The valley constraint: ； The valley value superposition condition is: ； The peak superposition condition is: ； in, , Respectively represent the maximum value, represents the peak total dose, Indicates dosage unit, Indicates the total trough dose.

7. The lattice space fractionation radiotherapy method based on the adaptive precise dose superposition model according to claim 4, characterized in that: The S5 comprises the following steps: S5-1. Set treatment time threshold and dosage threshold; S5-2, determining an initial value of the dose contribution ratio based on the initial value of the peak contribution ratio; S5-3, based on the SRS treatment plan, the VMAT treatment plan and the initial value of the dose contribution ratio, respectively, the SRS spatial dose distribution model and the VMAT spatial dose compensation model are used to sequentially perform SRS treatment and VMAT treatment on the lattice target area of ​​the patient, and the treatment is monitored to obtain a monitoring treatment time; S5-4, calculating the corresponding cumulative spatial dose value; obtaining the spatial dose distribution diagram of the current state through the total dose spatial distribution model; S5-5, determine whether the cumulative spatial dose value exceeds the dose threshold; if so, end the lattice space fractionation radiotherapy; otherwise, enter S5-6; S5-6, judging whether the monitoring treatment time exceeds the treatment time threshold; if so, proceeding to S5-7; otherwise, returning to S5-3; S5-7. Based on the spatial dose distribution diagram of the current state, update the peak contribution ratio and return to S5-3.

8. The lattice space fractionation radiotherapy method based on the adaptive precise dose superposition model according to claim 7, characterized in that: The S5-3 comprises the following steps: S5-3-1, based on the SRS treatment plan and the initial value of the dose contribution ratio, determine the peak dose through the SRS spatial dose distribution model; S5-3-2, based on the peak dose, performing SRS treatment and monitoring on the lattice target area of ​​the patient; S5-3-3, based on the VMAT treatment plan and the initial value of the dose contribution ratio, determining the valley dose by using the VMAT spatial dose compensation model; S5-3-4. Based on the trough dose, VMAT treatment and monitoring are performed on the patient's lattice target area to obtain a corresponding monitoring treatment time.

9. The lattice space fractionation radiotherapy method based on the adaptive precise dose superposition model according to claim 7, characterized in that: The S5-7 comprises the following steps: S5-7-1, updating the dose contribution ratio according to the monitored treatment time to obtain an updated dose contribution ratio; S5-7-2, judging whether the dose contribution ratio after the one-time update satisfies the dose constraint condition; if so, taking the dose contribution ratio after the one-time update as the dose contribution ratio of the current state; otherwise, taking the dose contribution ratio as the dose contribution ratio of the current state; and proceeding to S5-7-3; S5-7-3, perform uniformity evaluation on the current spatial dose distribution diagram to obtain the corresponding uniformity evaluation result; S5-7-4. Based on the uniformity evaluation result and the patient's tolerance, dynamically fine-tune the dose contribution ratio of the current state to obtain a corresponding fine-tuned dose contribution ratio; S5-7-5. Based on the fine-tuned dose contribution ratio, update the peak contribution ratio and return to S5-3.

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