CN117653927A - Dose verification method, device and equipment for radiotherapy process - Google Patents

Abstract

The application relates to the technical field of dose verification, and provides a dose verification method, device, equipment and storage medium for a radiotherapy process, which can realize dose verification of the radiotherapy process under a full-field. In the application, a beam determined based on a radiation treatment plan is irradiated on an electronic portal imaging device to obtain a full portal image; determining an energy flux distribution image when the beam exits based on the full-field image; obtaining actual in-vivo dose distribution of the target object based on the energy flux distribution image and the medical image of the target object; and comparing the actual in-vivo dose distribution with the planned in-vivo dose distribution, and performing dose verification on the radiotherapy process.

Description

Dose verification method, device and equipment for radiotherapy process

Technical Field

The present application relates to the field of dose verification technology, and in particular, to a dose verification method, a dose verification device, a dose verification apparatus, a storage medium and a computer program product for a radiotherapy process.

Background

In the whole process of radiotherapy, dose verification is a vital link of 'accurate radiotherapy', and is mainly used for verifying the difference between the planned dose and the actual dose. With the development of radiotherapy, there are corresponding dose verifications at different stages, such as dose verification before radiotherapy and dose verification in radiotherapy process.

Dose verification at different stages can be performed by means of an electronic portal imaging device (EPID, electronic portal imaging device). However, in the radiotherapy of the target object, the bed plate for placing the target object is located between the treatment head and the EPID, the EPID is difficult to approach the treatment head, the distance between the EPID and the treatment head is limited, and when the beam is irradiated on the EPID with limited sensing area of the EPID, the EPID can only sense part of the beam, and is difficult to sense all of the beam, and in the radiotherapy, only dose verification of the local field is difficult to perform, and dose verification of the full field is difficult to perform.

Disclosure of Invention

Based on this, it is necessary to provide a dose verification method, apparatus, dose verification device, storage medium and computer program product for radiotherapy process in view of the above technical problems.

The present application provides a dose verification method for a radiotherapy procedure, the method comprising:

irradiating the beam determined based on the radiotherapy plan on an electronic portal imaging device to obtain a full portal image;

determining an energy flux distribution image when the beam exits based on the full field image;

obtaining an actual in-vivo dose distribution of the target object based on the energy flux distribution image and a medical image of the target object;

and comparing the actual in-vivo dose distribution with the planned in-vivo dose distribution, and performing dose verification on the radiotherapy process.

The present application provides a dose verification device for a radiotherapy procedure, the device comprising:

the full-field image acquisition module is used for irradiating the beam determined based on the radiotherapy plan to the electronic field imaging equipment to obtain a full-field image;

the energy flux distribution acquisition module is used for determining an energy flux distribution image when the beam exits based on the full-field image;

the dose distribution determining module is used for obtaining the actual in-vivo dose distribution of the target object based on the energy flux distribution image and the medical image of the target object;

and the dose verification module is used for comparing the actual in-vivo dose distribution with the planned in-vivo dose distribution and carrying out dose verification on the radiotherapy process.

The present application provides a dose verification device comprising a memory storing a computer program and a processor executing the above method.

The present application provides a computer readable storage medium having stored thereon a computer program for execution by a processor of the above method.

The present application provides a computer program product having a computer program stored thereon, the computer program being executed by a processor to perform the above method.

In the method, before radiotherapy of a target object, a beam obtained based on a radiotherapy plan is irradiated on electronic portal imaging equipment to obtain a full portal image, so that an energy flux distribution image determined based on the full portal image when the beam exits corresponds to the full portal; and then, according to the energy flux distribution image and the medical image of the target object, evaluating the actual in-vivo dose distribution of the target object in the radiotherapy process, wherein the actual in-vivo dose distribution also corresponds to the full-field, and then, comparing the actual in-vivo dose distribution under the full-field with the planned in-vivo dose distribution to realize the dose verification of the radiotherapy process under the full-field.

Drawings

FIG. 1 is a schematic view of a treatment apparatus in one embodiment;

FIG. 2 is a schematic illustration of illumination areas where beams are formed at different distances in one embodiment;

FIG. 3 is a schematic diagram of the relative positions between the illuminated area and the EPID at different distances in one embodiment;

FIG. 4 is a flow chart of a method of dose verification of a treatment session in one embodiment;

FIG. 5 is a flow chart of a dose verification method of a treatment procedure in another embodiment;

FIG. 6 is a block diagram of a dose verification device for a treatment session in one embodiment;

fig. 7 is an internal structural diagram of the dose verification device in one embodiment.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application will be further described in detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the present application.

Reference in the specification to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly understand that the embodiments described herein may be combined with other embodiments.

The application provides a dose verification method for a radiotherapy process, which belongs to the field of radiotherapy, wherein radiotherapy equipment can be annular Linac, CT-Linac, MR-Linac and PET-MR-Linac, and a structural schematic diagram of the radiotherapy equipment is shown in figure 1.

The treatment head 110 may emit a beam that forms an irradiated area of a corresponding size at various distances from the treatment head 110, as shown in fig. 2, the beam forming an irradiated area of a size of 40cm x 40cm at 100cm from the treatment head, and the beam forming an irradiated area of a size of 58cm x 58cm at 145cm from the treatment head.

The treatment head 110 may be disposed opposite the EPID 130, and the EPID 130 is provided with a sensing area for sensing a beam irradiated onto the EPID 130, and a corresponding image is formed according to information sensed by the sensing area. With the size of the sensing area fixed, referring to fig. 3, as EPID 130 is farther from treatment head 110, the beam-formed irradiation area gradually changes from falling entirely within the sensing area to falling partially within the sensing area.

When the distance between the EPID 130 and the treatment head 110 is within a specific range, the irradiation area formed by the beam falls entirely within the sensing area of the EPID 130, in which case an image formed according to information sensed by the sensing area of the EPID 130 may be referred to as a full-field image; wherein any distance within the particular range may be referred to as a particular distance.

When the distance between the EPID 130 and the treatment head 110 exceeds a certain range, the irradiated area formed by the beam falls partially within the sensing area of the EPID 130, in which case the image formed according to the information sensed by the sensing area of the EPID 130 is a non-full-field image.

In the radiotherapy process of the target object, the target object is placed on the bed board 120 shown in fig. 1, the bed board 120 is located between the treatment head 110 and the EPID 130, the distance between the treatment head 110 and the EPID 130 is limited by the blocking of the bed board 120, under the condition that the distance is limited by the bed board, the irradiation area formed by the beam may not fall in the sensing area of the EPID 130 completely, and the image formed according to the information sensed by the sensing area of the EPID 130 may be a non-full field image; thus, it is difficult to evaluate the actual in-vivo dose distribution of the target subject in the whole field, and it is difficult to perform dose verification of the radiotherapy process in the whole field.

To achieve dose verification of radiation therapy procedures in the full field, the present application provides a method comprising the steps of:

step S401, the beam determined based on the radiotherapy plan is irradiated to the electronic portal image equipment, and a full portal image is obtained.

Wherein the radiation treatment plan is formulated for the target object, which may be a radiation treatment planning system; the radiation treatment plan may provide information about the beam emitted by the treatment head during radiation treatment. The full-field image is: the irradiation area formed by the beam falls in the sensing area of the EPID, and an image is formed according to the information sensed by the sensing area of the EPID; the full field image may be a gray scale image.

Further, the step of irradiating the beam determined based on the radiotherapy plan to the electronic portal imaging device to obtain a full portal image may specifically include: and under the condition that the distance between the electronic portal image equipment and the treatment head is a specific distance, controlling the treatment head to emit a beam based on a radiation treatment plan so that an irradiation area formed by the beam at the specific distance falls in a sensing area of the electronic portal image equipment, and obtaining a full portal image through the electronic portal image equipment.

Still further, the step of adjusting the distance between the electronic portal imaging device and the treatment head to a specific distance includes: before radiotherapy of a target object, controlling the electronic portal imaging equipment to move to an isocenter plane; when the electronic portal imaging device is located in the isocenter plane, the distance between the electronic portal imaging device and the treatment head is determined to be adjusted to a specific distance.

In general, the intersection of the axis of rotation of the radiotherapy apparatus gantry and the axis of rotation of the treatment head 110 may be referred to as an isocenter; in some specially constructed radiotherapy apparatus, the distance of the isocenter from the treatment head 110 may be 100cm as shown in fig. 2. The plane passing through the isocenter and perpendicular to the direction in which the treatment head 110 emits the beam may be referred to as an isocenter plane.

Typically, when EPID 130 is located in the isocenter plane, the irradiation area formed by the beam at the corresponding distance (distance of treatment head 110 from the isocenter) may fall entirely within the sensing area of EPID 130. Thus, prior to radiation treatment of the target subject, EPID 130 may be controlled to move to the isocenter plane; when the EPID 130 is located on the isocenter plane, it is determined that the distance between the EPID 130 and the treatment head 110 is within a specific range, that is, the distance between the EPID 130 and the treatment head 110 is adjusted to a specific distance, at which time, when the treatment head 110 emits the beam, the irradiation area formed by the beam at the specific distance falls entirely within the sensing area of the EPID 130, and a full-field image is formed according to information sensed by the sensing area of the EPID 130.

Before the EPID 130 is moved to the isocenter plane, the couch 120 may be controlled to move between the treatment head 110 and the EPID 130 before the target subject is treated, and thus the EPID 130 is controlled to move to the isocenter plane, considering that the couch 120 may cause blockage to the EPID 130.

Step S402, determining an energy flux distribution image at the time of beam emission based on the full field image.

Step S403, obtaining an actual in-vivo dose distribution of the target object based on the energy flux distribution image and the medical image of the target object.

In step S404, the actual in-vivo dose distribution is compared with the planned in-vivo dose distribution, and the radiotherapy process is subjected to dose verification.

Wherein the medical image of the target object is used to describe the anatomy of the target object, which may be a tomographic image; the medical image of the target object may be a medical image used for preparing a radiation treatment plan, or may be an image obtained by scanning the target object on the day of radiotherapy.

In this embodiment, the full-field image obtained before radiotherapy is used to determine an energy flux distribution image when the beam exits, and then, according to the energy flux distribution image and anatomical structure information carried by the medical image of the target object, the dose deposition condition of the beam in the body of the target object is simulated to obtain the actual in-vivo dose distribution of the target object. Since the energy path distribution image corresponds to the full field, the resulting actual in vivo dose distribution also corresponds to the full field.

After the actual in-vivo dose distribution corresponding to the full field is obtained, the actual in-vivo dose distribution is compared with the planned in-vivo dose distribution so as to carry out dose verification in the radiotherapy process under the full field.

In the dose verification method in the radiotherapy process, before the radiotherapy of the target object, the beam obtained based on the radiotherapy plan is irradiated on the electronic portal image equipment to obtain a full portal image, so that the energy flux distribution image determined based on the full portal image when the beam exits corresponds to the full portal; and then, according to the energy flux distribution image and the medical image of the target object, evaluating the actual in-vivo dose distribution of the target object in the radiotherapy process, wherein the actual in-vivo dose distribution also corresponds to the full-field, and then, comparing the actual in-vivo dose distribution under the full-field with the planned in-vivo dose distribution to realize the dose verification of the radiotherapy process under the full-field.

In one embodiment, step S402 may specifically include the following steps: deconvolution processing is carried out on the full-field image to obtain an energy flux distribution image when the beam exits; alternatively, the full-field image is input into a model obtained by a machine learning method, and an energy flux distribution image at the time of beam emission is obtained.

In this embodiment, the energy flux distribution image at the time of beam emission (i.e., at the time of beam just leaving the treatment head) is obtained by deconvolution or by machine learning.

If the deconvolution mode is adopted, the convolution kernel used in the deconvolution mode needs to be determined in a plurality of attempts; specifically, the step of obtaining a convolution kernel for deconvolution processing includes: acquiring a sample energy flux distribution image when a sample beam exits, and acquiring a sample full-field image obtained by the sample beam acting on an electronic field imaging device; and adjusting the convolution kernel until the consistency between the full-field image obtained by the adjusted convolution kernel acting on the sample energy flux distribution image and the sample full-field image is higher than a threshold value.

If the model is a machine learning mode, a reasonable model can be learned through a large number of ideal energy flux distribution images and full-field images acquired by EPID, and the model can be a model constructed based on a Monte Carlo algorithm or a convolutional neural network model (such as a unet model); specifically, the step of obtaining the model based on the machine learning mode includes: obtaining a training sample, wherein the training sample comprises sample energy flux distribution when a sample beam exits and a sample full-field image of the sample beam acting on the electronic field imaging device; and performing machine learning by using the training sample to obtain a model.

If the medical image is a tomographic image, step S403 may specifically include: based on the energy flux distribution map and the tomographic image of the target object, the dose deposition condition of the beam in the body of the target object is simulated, and the actual in-vivo dose distribution of the target object is obtained.

The tomographic image can be obtained directly from CBCT, CT, MR, PET-CT, PET-MR, etc., or can be obtained by converting PET, SPECT. Because the tomographic image carries anatomical structure information of the target object, the dose deposition condition of the beam in the body of the target object can be simulated according to the energy flux distribution map and the tomographic image of the target object, so as to obtain the actual in-vivo dose distribution of the target object.

In order to better understand the above method, an application example of the dose verification method of the radiotherapy procedure of the present application will be described in detail below with reference to fig. 5, where the application embodiment specifically includes the following steps:

before radiotherapy of a target object, controlling the bed board to move out between the treatment head and the electronic portal image equipment, and controlling the electronic portal image equipment to move to an isocenter plane;

when the electronic portal image equipment is positioned on the isocenter plane, determining that the distance between the electronic portal image equipment and the treatment head is adjusted to a specific distance;

controlling the treatment head to emit a beam based on a radiation treatment plan under the condition that the distance between the electronic portal imaging equipment and the treatment head is a specific distance, so that an irradiation area formed by the beam at the specific distance falls in a sensing area of the electronic portal imaging equipment, and obtaining a full portal image through the electronic portal imaging equipment;

deconvolution processing is carried out on the full-field image to obtain an energy flux distribution image when the beam exits, or the full-field image is input into a model obtained based on a machine learning mode to obtain the energy flux distribution image when the beam exits;

simulating the dose deposition condition of the beam in the body of the target object based on the energy flux distribution map and the tomographic image of the target object to obtain the actual in-body dose distribution of the target object;

and comparing the actual in-vivo dose distribution with the planned in-vivo dose distribution, and performing dose verification on the radiotherapy process.

In the application example, the full-field image is obtained by dose verification before radiotherapy, and the energy flux distribution image after the beam leaves the treatment head is obtained by deconvolution or machine learning. Then calculating the dose distribution in the target object according to the modeled convolution kernel or Monte Carlo algorithm and the originally planned tomographic image of the target object or the tomographic image of the current day, and then confirming the accuracy of dose projection through different comparison algorithms, so that the dose verification of the radiotherapy process under the full field is realized, and the limit that only the beam of a smaller field can be processed due to the EPID position is solved.

It should be understood that, although the steps in the flowcharts related to the embodiments described above are sequentially shown as indicated by arrows, these steps are not necessarily sequentially performed in the order indicated by the arrows. The steps are not strictly limited to the order of execution unless explicitly recited herein, and the steps may be executed in other orders. Moreover, at least some of the steps in the flowcharts described in the above embodiments may include a plurality of steps or a plurality of stages, which are not necessarily performed at the same time, but may be performed at different times, and the order of the steps or stages is not necessarily performed sequentially, but may be performed alternately or alternately with at least some of the other steps or stages.

In one embodiment, as shown in fig. 6, there is provided a dose verification device for a radiotherapy procedure, comprising:

the full-field image acquisition module 601 is configured to irradiate a beam determined based on a radiation treatment plan on an electronic field imaging device to obtain a full-field image;

an energy flux distribution acquisition module 602, configured to determine an energy flux distribution image when the beam exits based on the full field image;

a dose distribution determination module 603, configured to obtain an actual in-vivo dose distribution of the target object based on the energy flux distribution image and a medical image of the target object;

the dose verification module 604 is configured to compare the actual in-vivo dose distribution with the planned in-vivo dose distribution, and perform dose verification on the radiotherapy process.

In one embodiment, the energy flux distribution acquisition module 602 is further configured to perform deconvolution on the full-field image to obtain an energy flux distribution image when the beam exits; or, the full-field image is input into a model obtained based on a machine learning mode, and an energy flux distribution image when the beam is emitted is obtained.

In one embodiment, the device further comprises a convolution kernel acquisition module, which is used for acquiring a sample energy flux distribution image when the sample beam exits and acquiring a sample full-field image obtained by the sample beam acting on the electronic field imaging device; and adjusting the convolution kernel until the consistency between the full-field image obtained by the adjusted convolution kernel acting on the sample energy flux distribution image and the sample full-field image is higher than a threshold value.

In one embodiment, the apparatus further comprises a model acquisition module for acquiring a training sample, wherein the training sample comprises a sample energy flux distribution when a sample beam exits and a sample full-field image of the sample beam acting on the electronic field imaging device; and performing machine learning by using the training sample to obtain the model.

In one embodiment, the medical image is a tomographic image, and the dose distribution determining module 603 is further configured to simulate a dose deposition condition of the beam in the body of the target object based on the energy flux distribution map and the tomographic image of the target object, so as to obtain an actual in-vivo dose distribution of the target object.

In one embodiment, the full-field image acquisition module 601 is further configured to, when the distance between the electronic field imaging device and the treatment head is a specific distance, control the treatment head to emit a beam based on a radiotherapy plan, so that an irradiation area formed by the beam at the specific distance falls within a sensing area of the electronic field imaging device, and obtain a full-field image through the electronic field imaging device.

In one embodiment, the device further comprises a distance adjusting module, which is used for controlling the electronic portal imaging equipment to move to the isocenter plane before radiotherapy of the target object; when the electronic portal imaging device is located in the isocenter plane, the distance between the electronic portal imaging device and the treatment head is determined to be adjusted to a specific distance.

In one embodiment, the distance adjusting module is further used for controlling the bed board to move out between the treatment head and the electronic portal imaging device before radiotherapy of the target object, and controlling the electronic portal imaging device to move to the isocenter plane.

For specific limitations of the dose verification device for radiotherapy procedures, reference may be made to the above limitations of the dose verification method for radiotherapy procedures, and no further description is given here. The modules in the dose verification device of the radiotherapy process can be realized in whole or in part by software, hardware and a combination thereof. The modules can be embedded in hardware or independent of a processor in the dose verification device, or can be stored in a memory in the dose verification device in a software mode, so that the processor can call and execute the corresponding operations of the modules.

In one embodiment, a dose verification device is provided, the internal structure of which may be as shown in fig. 7. The dose verification device comprises a processor, a memory and a network interface connected by a system bus. Wherein the processor of the dose verification device is adapted to provide computing and control capabilities. The memory of the dose verification device comprises a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, computer programs, and a database. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage media. The database of the dose verification device is used for storing dose verification data of the radiotherapy process. The network interface of the dose verification device is adapted to communicate with an external terminal via a network connection. The dose verification device also comprises an input/output interface, wherein the input/output interface is a connecting circuit for exchanging information between the processor and external equipment, and the input/output interface is connected with the processor through a bus and is called as an I/O interface for short. The computer program when executed by a processor implements a dose verification method of a radiotherapy procedure.

It will be appreciated by persons skilled in the art that the structure shown in fig. 7 is merely a block diagram of some of the structures associated with the present application and does not constitute a limitation of the dose verification device to which the present application is applied, and that a particular dose verification device may comprise more or less components than shown in the figures, or may combine certain components, or have a different arrangement of components.

In one embodiment, a dose verification device is provided comprising a memory storing a computer program and a processor implementing the steps of the method embodiments described above when the processor executes the computer program.

In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored which, when executed by a processor, carries out the steps of the respective method embodiments described above.

In one embodiment, a computer program product is provided, on which a computer program is stored, which computer program is executed by a processor for performing the steps of the various method embodiments described above.

It should be noted that, user information (including but not limited to user equipment information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, presented data, etc.) referred to in the present application are information and data authorized by the user or sufficiently authorized by each party.

Those skilled in the art will appreciate that implementing all or part of the above-described methods may be accomplished by way of a computer program stored on a non-transitory computer readable storage medium, which when executed may comprise the steps of the embodiments of the methods described above. Any reference to memory, storage, database, or other medium used in embodiments provided herein may include at least one of non-volatile and volatile memory. The nonvolatile Memory may include Read-Only Memory (ROM), magnetic tape, floppy disk, flash Memory, optical Memory, or the like. Volatile memory can include random access memory (Random Access Memory, RAM) or external cache memory. By way of illustration, and not limitation, RAM can be in the form of a variety of forms, such as static random access memory (Static Random Access Memory, SRAM) or dynamic random access memory (Dynamic Random Access Memory, DRAM), and the like.

The technical features of the above embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The foregoing examples represent only a few embodiments of the present application, which are described in more detail and are not to be construed as limiting the scope of the invention. It should be noted that it would be apparent to those skilled in the art that various modifications and improvements could be made without departing from the spirit of the present application, which would be within the scope of the present application. Accordingly, the scope of protection of the present application is to be determined by the claims appended hereto.

Claims (10)

1. A method of dose verification for a radiation therapy procedure, the method comprising:

irradiating the beam determined based on the radiotherapy plan on an electronic portal imaging device to obtain a full portal image;

determining an energy flux distribution image when the beam exits based on the full field image;

obtaining an actual in-vivo dose distribution of the target object based on the energy flux distribution image and a medical image of the target object;

and comparing the actual in-vivo dose distribution with the planned in-vivo dose distribution, and performing dose verification on the radiotherapy process.

2. The method of claim 1, wherein the determining an energy flux distribution image at the beam exit based on the full field image comprises:

deconvolution processing is carried out on the full-field image to obtain an energy flux distribution image when the beam exits;

or, the full-field image is input into a model obtained based on a machine learning mode, and an energy flux distribution image when the beam is emitted is obtained.

3. The method of claim 2, wherein the step of obtaining a convolution kernel for the deconvolution process comprises:

acquiring a sample energy flux distribution image when a sample beam exits, and acquiring a sample full-field image obtained by the sample beam acting on an electronic field imaging device;

and adjusting the convolution kernel until the consistency between the full-field image obtained by the adjusted convolution kernel acting on the sample energy flux distribution image and the sample full-field image is higher than a threshold value.

4. The method of claim 2, wherein the step of deriving the model based on machine learning comprises:

acquiring a training sample, wherein the training sample comprises sample energy flux distribution when a sample beam exits and a sample full-field image of the sample beam acting on electronic field imaging equipment;

and performing machine learning by using the training sample to obtain the model.

5. The method according to claim 1, wherein the medical image is a tomographic image, the deriving an actual in-vivo dose distribution of the target object based on the energy flux distribution image and the medical image of the target object comprises:

and simulating the dose deposition condition of the beam in the body of the target object based on the energy flux distribution map and the tomographic image of the target object, and obtaining the actual in-body dose distribution of the target object.

6. The method of any one of claims 1 to 5, wherein irradiating the beam determined based on the radiation treatment plan to the electronic portal imaging device results in a full portal image, comprising:

and under the condition that the distance between the electronic portal image equipment and the treatment head is a specific distance, controlling the treatment head to emit a beam based on a radiation treatment plan so that an irradiation area formed by the beam at the specific distance falls in a sensing area of the electronic portal image equipment, and obtaining a full portal image through the electronic portal image equipment.

7. The method of claim 6, wherein the step of adjusting the distance between the electronic portal imaging device and the treatment head to a specific distance comprises:

before radiotherapy of a target object, controlling the electronic portal imaging equipment to move to an isocenter plane;

when the electronic portal imaging device is located in the isocenter plane, the distance between the electronic portal imaging device and the treatment head is determined to be adjusted to a specific distance.

8. The method of claim 7, wherein controlling the electronic portal imaging device to move to an isocenter plane prior to radiation therapy of the target subject comprises:

before radiotherapy of a target object, the bed board is controlled to move out between the treatment head and the electronic portal imaging equipment, and the electronic portal imaging equipment is controlled to move to an isocenter plane.

9. A dose verification device for a radiation therapy procedure, the device comprising:

the full-field image acquisition module is used for irradiating the beam determined based on the radiotherapy plan to the electronic field imaging equipment to obtain a full-field image;

the energy flux distribution acquisition module is used for determining an energy flux distribution image when the beam exits based on the full-field image;

the dose distribution determining module is used for obtaining the actual in-vivo dose distribution of the target object based on the energy flux distribution image and the medical image of the target object;

and the dose verification module is used for comparing the actual in-vivo dose distribution with the planned in-vivo dose distribution and carrying out dose verification on the radiotherapy process.

10. Dose verification device comprising a memory and a processor, the memory storing a computer program, characterized in that the processor implements the method of any one of claims 1 to 8 when executing the computer program.