Method and device for acquiring sub-field information based on real-time dose guidance

Abstract

The invention discloses a method and equipment for acquiring sub-field information based on real-time dose guidance. The method comprises the following steps of: acquiring a real-time dose in a radiotherapy process by utilizing EPID (Enhanced Proportion Integration Differentiation); according to the real-time dose obtained by the EPID, obtaining the actual cumulative dose # imgabs0 # of the target region of the patient at the t moment, obtaining the planned cumulative dose # imgabs1 # of the target region of the patient at the t + 1 moment, and predicting the target region mobility f at the t + 1 moment based on the multi-modal image in a radiotherapy planned dose table; according to a corresponding formula, sub-field information A about to be irradiated at the moment of (t, t + 1) is solved; and repeating the steps until the radiotherapy is finished. According to the method, the real-time accumulated dose of a patient in the treatment process is obtained through EPID, the change of the position and shape of a target area is predicted in combination with a multi-modal image, the difference between the real-time dose and the planned dose is speculated, sub-field information at the next moment is obtained, and the dose is monitored in the whole process.

Description

Technical Field

[0001] The present invention belongs to the technical field of radiotherapy, and in particular relates to a method and device for acquiring sub-field information based on real-time dose guidance. Background Art

[0002] Radiotherapy is an important means of cancer treatment, using high-energy radiation to destroy tumor cells. To ensure the effectiveness of treatment, image-guided radiotherapy (IGRT) and tumor tracking technology use advanced medical imaging technologies such as CBCT and kV X-rays to monitor changes in tumor position and morphology in real time and adjust the treatment plan to accurately irradiate tumor tissue while minimizing damage to surrounding normal tissues.

[0003] The electronic portal imaging device (EPID) is a commonly used imaging device that can obtain the dose distribution of patients receiving radiotherapy in real time, thereby performing in-vivo dose verification.

[0004] The application of these technologies has improved the accuracy and safety of radiotherapy, providing patients with more effective personalized treatment plans.

[0005] EPID dose reconstruction is mainly used for preoperative dose verification and in vivo dose verification. Among them, EPID can obtain the dose after passing through the human body during the treatment process, reverse the actual dose received by the patient, and realize in vivo dose verification.

[0006] In terms of image guidance, the CyberKnife's kV imaging system can also provide the patient's imaging information during the treatment process, which can be used for preoperative positioning and intraoperative position adjustment.

[0007] Although existing radiotherapy technology guarantees the accuracy of radiation dose to a certain extent, there are still some problems.

[0008] First, existing dose verification methods mainly focus on the preoperative and in vivo stages, and cannot achieve full-process dose monitoring and provide a reference during the treatment process.

[0009] Secondly, although image-guided technology can improve the precision of radiotherapy and ensure the accuracy of the position during treatment, most of the current image-guided devices can only provide tumor contours, cannot accurately predict the shape changes of the tumor, and cannot guarantee the accuracy of the dose. Summary of the invention

[0010] In order to solve the above technical problems, the present invention proposes a method and device for acquiring sub-field information based on real-time dose guidance.

[0011] In order to achieve the above object, the technical solution of the present invention is as follows:

[0012] In one aspect, the present invention discloses a method for acquiring sub-field information based on real-time dose guidance, comprising:

[0013] Step S1: using EPID to obtain the real-time dose during radiotherapy;

[0014] Step S2: Obtain the actual cumulative dose of the patient's target area at time t based on the real-time dose obtained by EPID

[0015] Step S3: Obtain the cumulative dose of the target area planned for the patient at time t+1 in the radiotherapy plan dose table

[0016] Step S4: predicting the target area motion f at time t+1 based on the multimodal images;

[0017] Step S5: According to the following formula, obtain the sub-field information A to be irradiated at the time (t, t+1);

[0018]

[0019] Where: d(f,A) is the dose irradiated by sub-field information A at time t+1 under the target area motion f;

[0020] Step S6: Repeat steps S1 to S5 until the radiotherapy is completed.

[0021] Based on the above technical solution, the following improvements can be made:

[0022] As a preferred solution, step S2 includes:

[0023] Step S2.1: Calculate the target dose in the patient's body during the time period (t-1, t] according to the real-time dose obtained by EPID

[0024] Step S2.2: Obtain the actual cumulative dose of the patient in the target area at time t by the following formula:

[0025] in: is the actual cumulative dose of the patient in the target area at time t-1.

[0026] As a preferred solution, step S3 includes:

[0027] Step S3.1: Extract the target area planned cumulative dose for the time period (t, t+1] in the radiotherapy plan dose table

[0028] Step S3.2: Obtain the patient's target volume cumulative dose at time t+1 by the following formula:

[0029]

[0030] in: Plan the cumulative dose to the target volume for the patient at time t.

[0031] As a preferred solution, the target area movement f includes: position change of the target area in the LAT direction, position change of the target area in the LNG direction, position change of the target area in the VRT direction, and shape change of the target area in the BEV direction.

[0032] On the other hand, the present invention also discloses a sub-field information acquisition device based on real-time dose guidance, comprising:

[0033] Real-time dose acquisition module, used to obtain real-time dose during radiotherapy using EPID;

[0034] The actual cumulative dose acquisition module is used to obtain the actual cumulative dose of the patient's target area at time t based on the real-time dose obtained by EPID

[0035] The planned cumulative dose acquisition module is used to obtain the patient's target area planned cumulative dose at time t+1 in the radiotherapy plan dose table.

[0036] A prediction module is used to predict the target area motion f at time t+1 based on multimodal images;

[0037] The sub-field information obtaining module is used to obtain the sub-field information A to be irradiated at the time (t, t+1] according to the following formula;

[0038]

[0039] Where: d(f,A) is the dose irradiated by sub-field information A at time t+1 under the target area motion f;

[0040] The repeated execution module is used to repeatedly execute the methods in the real-time dose acquisition module, the actual cumulative dose acquisition module, the planned cumulative dose acquisition module, the prediction module, and the sub-field information acquisition module until the radiotherapy is completed.

[0041] As a preferred solution, the actual cumulative dose acquisition module includes:

[0042] The first processing unit of actual cumulative dose is used to calculate the target dose in the human body of the patient in the time period (t-1, t] according to the real-time dose obtained by EPID

[0043] The actual cumulative dose second processing unit is used to obtain the actual cumulative dose of the patient's target area at time t by the following formula:

[0044]

[0045] in: is the actual cumulative dose of the patient in the target area at time t-1.

[0046] As a preferred solution, the planned cumulative dose acquisition module includes:

[0047] The first processing unit of the planned cumulative dose is used to extract the target area planned cumulative dose in the (t, t+1] time period in the radiotherapy planned dose table

[0048] The second processing unit for planned cumulative dose is used to obtain the planned cumulative dose of the target area of ​​the patient at time t+1 by the following formula:

[0049]

[0050] in: Plan the cumulative dose to the target volume for the patient at time t.

[0051] As a preferred solution, the target area movement f includes: position change of the target area in the LAT direction, position change of the target area in the LNG direction, position change of the target area in the VRT direction, and shape change of the target area in the BEV direction.

[0052] The present invention discloses a sub-field information acquisition method and device based on real-time dose guidance, which utilizes EPID to acquire the real-time cumulative dose of a patient during treatment, combines multimodal images to predict the change of target area position and shape, infers the difference between the real-time dose and the planned dose, acquires the sub-field information at the next moment, monitors the dose throughout the process, ensures the consistency of plan and execution, and improves the effect of radiotherapy. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] 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.

[0054] Figure 1 The present invention provides a flowchart of a method for obtaining sub-field information according to an embodiment of the present invention. DETAILED DESCRIPTION

[0055] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0056] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0057] Using ordinal numbers “first,” “second,” “third,” etc. to describe common objects merely indicates that different instances of similar objects are involved and is not intended to imply that the objects so described must have a given order in time, space, order, or in any other manner.

[0058] In addition, the expression of “comprising” an element is an “open” expression, which merely means that corresponding components or steps exist, and should not be interpreted as excluding additional components or steps.

[0059] In order to achieve the purpose of the present invention, in some embodiments of a method and device for acquiring sub-field information based on real-time dose guidance, as Figure 1 As shown, the method for obtaining sub-field information includes:

[0060] Step S1: using EPID to obtain the real-time dose during radiotherapy;

[0061] Step S2: Obtain the actual cumulative dose of the patient's target area at time t based on the real-time dose obtained by EPID

[0062] Step S3: Obtain the cumulative dose of the target area planned for the patient at time t+1 in the radiotherapy plan dose table

[0063] Step S4: predicting the target area motion f at time t+1 based on the multimodal images;

[0064] Step S5: According to the following formula, obtain the sub-field information A to be irradiated at the time (t, t+1);

[0065] Step S6: Repeat steps S1 to S5 until the radiotherapy is completed.

[0066]

[0067] Where: d(f,A) is the dose irradiated by sub-field information A at time t+1 under the target area motion f.

[0068] It is worth noting that at the initial moment t = 0, Both are 0.

[0069] Each step is described in detail below.

[0070] Step S1 uses an electronic portal imaging device (EPID) to obtain the real-time dose of the patient during treatment.

[0071] The specific operation is to install the EPID on the linear accelerator, set appropriate shooting parameters, such as exposure time, exposure dose, etc., and then perform radiotherapy on the patient. During the treatment, the EPID continuously captures radiation field images, and the above images are processed by existing technology to obtain the real-time dose of the EPID during the treatment process.

[0072] Further, step S2 comprises:

[0073] Step S2.1: Calculate the target dose in the patient's body during the time period (t-1, t] according to the real-time dose obtained by EPID

[0074] Step S2.2: Obtain the actual cumulative dose of the patient in the target area at time t by the following formula:

[0075] in: is the actual cumulative dose of the patient in the target area at time t-1.

[0076] Step S2: Based on the real-time dose obtained from EPID, the actual dose received by the patient is inferred, the dose of the patient in the time period (t-1, t] is calculated, and the target dose in the patient is extracted, which is recorded as The actual cumulative dose of the target area can be obtained

[0077] It is worth noting that for step S2.1, the real-time dose obtained according to EPID is used to calculate the target dose in the human body of the patient in the time period (t-1, t] The following two existing methods can be used but are not limited to: 1) using a correction-based algorithm to back-project the initial signal into the patient's anatomical structure information, 2) converting the acquired EPID field image into the patient's human radiation energy flux, and then using the energy flux as the input of the dose calculation algorithm, combined with the patient's CT data to obtain the patient's body point, two-dimensional or three-dimensional dose distribution. The conventional technical means in the field of the above method can be found in the article "Progress in In Vivo Dose Verification Based on EPID" published in the Chinese Journal of Radiation Oncology, which will not be repeated here.

[0078] Further, step S3 includes:

[0079] Step S3.1: Extract the target area planned cumulative dose for the time period (t, t+1] in the radiotherapy plan dose table

[0080] Step S3.2: Obtain the patient's target volume cumulative dose at time t+1 by the following formula:

[0081]

[0082] in: Plan the cumulative dose to the target volume for the patient at time t.

[0083] It is worth noting that if the radiotherapy plan dose table directly contains the cumulative dose of the target area at each moment, it can be directly extracted.

[0084] Furthermore, step S4 combines multimodal imaging technology (such as kV X-ray, structured light, ultrasound, etc.) to dynamically monitor the target area and predict the target area movement f at time t+1.

[0085] The target area movement f is specifically expressed as: f{x, y, z, d}.

[0086] Where: x represents the position change of the target area in the LAT direction;

[0087] y represents the position change in the LNG direction of the target area;

[0088] z represents the position change of the target area in the VRT direction;

[0089] d represents the shape change of the target field in the BEV direction.

[0090] Further, step S5 combines the real-time dose obtained by EPID, the target area motion prediction of multimodal imaging, and the planned dose. Specifically, the planned cumulative dose of the target area at time t+1 is calculated as Actual cumulative dose of the target area at time t And establish a mathematical relationship for the target area dynamics f{x, y, z, d} at time t+1.

[0091] Specifically, according to the predicted target area motion f and the sub-field information A irradiated in the time period (t, t+1], the expected irradiation dose d(f, A) is calculated, and the objective function is set:

[0092]

[0093] In particular, the sub-field A0 corresponding to the time (t, t+1] in the plan can be used as the initial solution. A is the optimal solution, that is, the sub-field information to be irradiated at (t, t+1].

[0094] The above-mentioned sub-field information generally includes the sub-field shape and the number of irradiation jumps.

[0095] The initial value of A (i.e., A0) is given by the plan. When making the plan, the default sub-field for irradiation at each moment will be obtained. By optimizing the sub-field at time t+1, the sub-field information with the minimum cumulative dose error (i.e., objective function) in the target area is obtained, which is used for the execution of the plan at the next moment.

[0096] Solution: Estimate the target voxel deposition matrix, and obtain the dose of each voxel in the target area under sub-field A by multiplying the target voxel deposition matrix with the sub-field information A.

[0097] The above can be solved by, but not limited to, the gradient method or simulated annealing. If the gradient method is used, the objective function is used to find the gradient of the sub-field shape, and after the shape is confirmed, the objective function is used to find the gradient of the irradiation time to obtain the local optimal sub-field information. If the simulated annealing method is used, a certain rule is used to change the sub-field information to obtain a better solution with a reduced target value.

[0098] The present invention uses an electronic portal imaging device (EPID) to obtain the real-time cumulative dose of the patient during the treatment process, and realizes in-vivo dose verification by inferring the actual dose received by the patient. At the same time, based on the real-time cumulative dose, the real-time dose received by the patient is calculated, so as to infer the difference between the planned dose and the real-time dose, adjust the plan, and achieve real-time dose-guided radiation therapy (DGRT).

[0099] The present invention combines multimodal imaging technologies, such as kV X-rays, structured light, and ultrasound, to dynamically monitor tumors and predict changes in the location and shape of tumors, thereby more accurately guiding radiotherapy.

[0100] In addition, an embodiment of the present invention further discloses a sub-field information acquisition device based on real-time dose guidance, comprising:

[0101] Real-time dose acquisition module, used to obtain real-time dose during radiotherapy using EPID;

[0102] The actual cumulative dose acquisition module is used to obtain the actual cumulative dose of the patient's target area at time t based on the real-time dose obtained by EPID

[0103] The planned cumulative dose acquisition module is used to obtain the patient's target area planned cumulative dose at time t+1 in the radiotherapy plan dose table.

[0104] A prediction module is used to predict the target area motion f at time t+1 based on multimodal images;

[0105] The sub-field information obtaining module is used to obtain the sub-field information A to be irradiated at the time (t, t+1] according to the following formula;

[0106]

[0107] Where: d(f,A) is the dose irradiated by sub-field information A at time t+1 under the target area motion f;

[0108] The repeated execution module is used to repeatedly execute the methods in the real-time dose acquisition module, the actual cumulative dose acquisition module, the planned cumulative dose acquisition module, the prediction module, and the sub-field information acquisition module until the radiotherapy is completed.

[0109] Furthermore, the actual cumulative dose acquisition module includes:

[0110] The first processing unit of actual cumulative dose is used to calculate the target dose in the human body of the patient in the time period (t-1, t] according to the real-time dose obtained by EPID

[0111] The actual cumulative dose second processing unit is used to obtain the actual cumulative dose of the patient's target area at time t by the following formula:

[0112]

[0113] in: is the actual cumulative dose of the patient in the target area at time t-1.

[0114] Furthermore, the planned cumulative dose acquisition module includes:

[0115] The first processing unit of the planned cumulative dose is used to extract the target area planned cumulative dose in the (t, t+1] time period in the radiotherapy planned dose table

[0116] The second processing unit for planned cumulative dose is used to obtain the planned cumulative dose of the target area of ​​the patient at time t+1 by the following formula:

[0117]

[0118] in: Plan the cumulative dose to the target volume for the patient at time t.

[0119] Furthermore, the target area movement f includes: the position change of the target area in the LAT direction, the position change of the target area in the LNG direction, the position change of the target area in the VRT direction, and the shape change of the target area in the BEV direction.

[0120] It should be understood that the various techniques described herein can be implemented in combination with hardware or software, or a combination thereof. Thus, the method and apparatus of the present invention, or some aspects or portions of the method and apparatus of the present invention, can take the form of program codes (i.e., instructions) embedded in a tangible medium, such as a floppy disk, a CD-ROM, a hard disk drive, or any other machine-readable storage medium, wherein when the program is loaded into a machine such as a computer and executed by the machine, the machine becomes a device for practicing the present invention.

[0121] In this embodiment, the specific content of the sub-field information acquisition device based on real-time dose guidance is similar to the content of the sub-field information acquisition method based on real-time dose guidance disclosed in the above embodiment, and will not be repeated here.

[0122] The present invention discloses a sub-field information acquisition method and device based on real-time dose guidance, which utilizes EPID to acquire the real-time cumulative dose of a patient during treatment, combines multimodal images to predict the change of target area position and shape, infers the difference between the real-time dose and the planned dose, acquires the sub-field information at the next moment, monitors the dose throughout the process, ensures the consistency of plan and execution, and improves the effect of radiotherapy.

[0123] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for illustrating the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which shall fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for acquiring sub-field information based on real-time dose guidance, characterized in that: include: Step S1: using EPID to obtain the real-time dose during radiotherapy; Step S2: Obtain the actual cumulative dose of the patient's target area at time t based on the real-time dose obtained by EPID Step S3: Obtain the cumulative dose of the target area planned for the patient at time t+1 in the radiotherapy plan dose table Step S4: predicting the target area motion f at time t+1 based on the multimodal images; Step S5: According to the following formula, obtain the sub-field information A to be irradiated at the time (t, t+1); Where: d(f,A) is the dose irradiated by sub-field information A at time t+1 under the target area motion f; Step S6: Repeat steps S1 to S5 until the radiotherapy is completed.

2. The method for obtaining sub-field information according to claim 1, characterized in that: The step S2 comprises: Step S2.1: Calculate the target dose in the patient's body during the time period (t-1, t] according to the real-time dose obtained by EPID Step S2.2: Obtain the actual cumulative dose of the patient in the target area at time t by the following formula: in: is the actual cumulative dose of the patient in the target area at time t-1.

3. The method for obtaining sub-field information according to claim 1, characterized in that: The step S3 comprises: Step S3.1: Extract the target area planned cumulative dose for the time period (t, t+1] in the radiotherapy plan dose table Step S3.2: Obtain the patient's target volume cumulative dose at time t+1 by the following formula: in: Plan the cumulative dose to the target volume for the patient at time t.

4. The method for obtaining sub-field information according to claim 1, characterized in that: The target area movement f includes: the position change of the target area in the LAT direction, the position change of the target area in the LNG direction, the position change of the target area in the VRT direction, and the shape change of the target area in the BEV direction.

5. A sub-field information acquisition device based on real-time dose guidance, characterized in that: include: Real-time dose acquisition module, used to obtain real-time dose during radiotherapy using EPID; The actual cumulative dose acquisition module is used to obtain the actual cumulative dose of the patient's target area at time t based on the real-time dose obtained by EPID The planned cumulative dose acquisition module is used to obtain the patient's target area planned cumulative dose at time t+1 in the radiotherapy plan dose table. A prediction module is used to predict the target area motion f at time t+1 based on multimodal images; The sub-field information obtaining module is used to obtain the sub-field information A to be irradiated at the time (t, t+1] according to the following formula; Where: d(f,A) is the dose irradiated by sub-field information A at time t+1 under the target area motion f; The repeated execution module is used to repeatedly execute the methods in the real-time dose acquisition module, the actual cumulative dose acquisition module, the planned cumulative dose acquisition module, the prediction module, and the sub-field information acquisition module until the radiotherapy is completed.

6. The subfield information acquisition device according to claim 5, characterized in that: The actual cumulative dose acquisition module comprises: The first processing unit of actual cumulative dose is used to calculate the target dose in the human body of the patient in the time period (t-1, t] according to the real-time dose obtained by EPID The actual cumulative dose second processing unit is used to obtain the actual cumulative dose of the patient's target area at time t by the following formula: in: is the actual cumulative dose of the patient in the target area at time t-1.

7. The sub-field information acquisition device according to claim 5, characterized in that: The planned cumulative dose acquisition module includes: The first processing unit of the planned cumulative dose is used to extract the target area planned cumulative dose in the (t, t+1] time period in the radiotherapy planned dose table The second processing unit for planned cumulative dose is used to obtain the planned cumulative dose of the target area of ​​the patient at time t+1 by the following formula: in: Plan the cumulative dose to the target volume for the patient at time t.

8. The sub-field information acquisition device according to claim 5, characterized in that: The target area movement f includes: the position change of the target area in the LAT direction, the position change of the target area in the LNG direction, the position change of the target area in the VRT direction, and the shape change of the target area in the BEV direction.

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