CN110582328B

CN110582328B - Radiotherapy emergent beam monitoring method and system

Info

Publication number: CN110582328B
Application number: CN201980001365.7A
Authority: CN
Inventors: 张艺宝; 黄宇亮; 吴昊; 李晨光
Original assignee: Beijing Institute for Cancer Research
Current assignee: Beijing Institute for Cancer Research
Priority date: 2019-07-22
Filing date: 2019-07-22
Publication date: 2022-03-01
Anticipated expiration: 2039-07-22
Also published as: CN110582328A; CN112512632A; WO2021013020A1; WO2021012149A1; CN112512632B

Abstract

The embodiment of the application discloses a radiotherapy emergent beam monitoring method and system. A radiation therapy exit beam monitoring method comprising: acquiring a reference image; the reference image is determined based on an imaged emergent beam image generated based on an emergent beam obtained by an imaged incident beam through a radiation object; acquiring a real-time treatment emergent beam image; the real-time treatment emergent beam image is generated based on an emergent beam obtained by a treatment incident beam penetrating through a radiation object in the current radiotherapy process; determining whether the difference of the pixel values of the real-time treatment emergent beam image and the reference image meets a preset condition or not; controlling the progress of the radiation therapy based on the judgment result; wherein the imaging input beam and the therapeutic input beam of the radiation therapy are homologous beams. The method and the device can monitor the outgoing beam dose of treatment, and ensure that the actual treatment meets the requirements of plan design.

Description

Radiotherapy emergent beam monitoring method and system

Technical Field

The present application relates to the field of radiotherapy equipment, and in particular, to a radiotherapy outgoing beam monitoring method and system.

Background

Before a patient is treated with radiation, it is often necessary to plan the patient with radiation using a radiation Treatment Planning System (TPS), determine a treatment plan, and then deliver treatment to the patient specifically according to the plan during the treatment session. To this end, the present application provides a method of monitoring emergent beam dose during radiation therapy.

Disclosure of Invention

One embodiment of the present application provides a radiotherapy emergent beam monitoring method. The radiotherapy emergent beam monitoring method comprises the following steps: acquiring a reference image; the reference image is determined based on an imaged emergent beam image generated based on an emergent beam obtained by an imaged incident beam through a radiation object; acquiring a real-time treatment emergent beam image; the real-time treatment emergent beam image is generated based on an emergent beam obtained by a treatment incident beam penetrating through a radiation object in the current radiotherapy process; determining whether the difference of the pixel values of the real-time treatment emergent beam image and the reference image meets a preset condition or not; controlling the progress of the radiation therapy based on the judgment result; wherein the imaging input beam and the therapeutic input beam of the radiotherapy are same-energy-level beams.

In some embodiments, the imaging input beam and the therapy input beam are from the same radiation source.

In some embodiments, the imaging exit beam image is acquired prior to radiation therapy.

In some embodiments, the imaged exit beam image is an image used for image-guided user positioning prior to radiation treatment.

In some embodiments, determining the reference image based on the imaged emergent beam image comprises: correcting the position coordinates of the imaging emergent beam image to obtain an initial reference image; and performing position matching on the initial reference image based on the treatment field to obtain a region corresponding to the treatment field in the initial reference image, and determining the region as the reference image.

In some embodiments, the performing position coordinate correction on the imaged emergent beam image to obtain an initial reference image includes: acquiring an imaging isocenter position and an isocenter position of a treatment plan; determining revised position coordinates based on a difference between the imaging isocenter position and the treatment plan isocenter position; and correcting the position coordinates of the imaging emergent beam image based on the corrected position coordinates.

In some embodiments, the performing position coordinate correction on the imaged emergent beam image to obtain an initial reference image further includes: acquiring the angle of a collimator during imaging and the collimator angle of a treatment plan; determining an angular difference between a collimator angle at imaging and a collimator angle of the treatment plan; and correcting the position coordinates of the imaging emergent beam image based on the angle difference.

In some embodiments, the position matching the initial reference image based on the treatment field to obtain a region in the initial reference image corresponding to the treatment field includes: determining a treatment field based on position data of the grating in the treatment plan to generate a mask image; and operating the mask image and the initial reference image to obtain the corresponding region.

In some embodiments, based on the treatment wild-to-mask image, further comprising: acquiring at least one treatment emergent beam image; determining boundary information of an actual treatment field based on the treatment emergent beam image; verifying the mask image based on the boundary information.

In some embodiments, determining the reference image based on the imaged emergent beam image comprises: determining a digital reconstructed image of the planned CT image; the planned CT image is a CT scanning image used for determining a treatment plan before treatment; obtaining an initial reference image based on the digital reconstructed image of the planned CT image and the imaged emergent beam image; and performing position matching on the initial reference image based on the treatment field to obtain a region corresponding to the treatment field in the initial reference image, and determining the region as the reference image.

In some embodiments, determining a digitally reconstructed image of the planning CT image comprises: according to S₀Exp (- μ Ι _ calculating a plurality of projection data; and determining a digitally reconstructed image of the planned CT image based on the plurality of projection data; wherein S is₀Subtracting a background value from an empty scanning signal, wherein the empty scanning signal is a signal collected by a detector when rays are only attenuated in the air, and the background value is an environmental signal collected by the detector when a radioactive source does not work; mu is the average attenuation coefficient of the ray passing through the human body from one direction; l is the length of the part of the body located in the linear distance between the detector and the planned CT radiation source.

In some embodiments, said deriving an initial reference image based on said planned CT digitally reconstructed image and said imaged exit beam image comprises: and carrying out deformation registration on the digital reconstruction image of the planned CT and the imaging emergent beam image based on an image registration algorithm to obtain the initial reference image.

In some embodiments, the determining whether the difference in pixel values between the real-time treatment exit beam image and the reference image satisfies a preset condition includes: determining the pixel value ratio of pixel points corresponding to the real-time treatment emergent beam image and the reference image; and judging whether the pixel value difference is within the tolerance range or not based on the pixel value ratio.

In some embodiments, the tolerance range is determined based on a combination of one or more of the following: signal to noise ratio, output factor, penumbra position, non-uniform ray effects or device stability factors.

In some embodiments, a simulation experiment is performed based on the treatment plan to obtain a simulated ratio of the treatment exit beam image and the reference fiducial image; an allowable range is determined based on the simulated ratio.

In some embodiments, the controlling radiation therapy progression based on the determination comprises: when the pixel value difference exceeds the tolerance range, the current treatment is stopped.

One of the embodiments of the present application provides a radiotherapy emergent beam monitoring system, including: the acquisition module is used for acquiring a reference image; the reference image is determined based on an imaged emergent beam image generated based on an emergent beam obtained by an imaged incident beam through a radiation object; the system is also used for acquiring a real-time treatment emergent beam image; the real-time treatment emergent beam image is generated based on an emergent beam obtained by a treatment incident beam penetrating through a radiation object in the current radiotherapy process; the judging module is used for judging whether the difference of the pixel values of the real-time treatment emergent beam image and the reference standard image meets a preset condition or not; the execution module is used for controlling the radiation treatment process based on the judgment result; wherein the imaging input beam and the therapeutic input beam of the radiotherapy are same-energy-level beams.

One of the embodiments of the present application provides a radiotherapy emergent beam monitoring device, which includes a processor, and the processor is configured to execute the radiotherapy emergent beam monitoring method.

One of the embodiments of the present application provides a computer-readable storage medium, which stores computer instructions, and when the computer instructions in the storage medium are read by a computer, the computer executes the foregoing radiation therapy emergent beam monitoring method.

One embodiment of the present application provides a method for acquiring a reference standard image for radiotherapy, including: acquiring an emergent beam obtained by the imaging incident beam penetrating through a radiation object, and generating an imaging emergent beam image based on the emergent beam; correcting the position coordinates of the imaging emergent beam image to obtain an initial reference image; performing position matching on the initial reference image based on the treatment field to obtain a region corresponding to the treatment field in the initial reference image, and determining the region as the reference image; wherein the imaging input beam and the therapeutic input beam of the radiotherapy are same-energy-level beams.

One embodiment of the present application provides a system for acquiring a reference image for radiotherapy, including: the acquisition module is used for acquiring an emergent beam obtained by the imaging incident beam penetrating through the radiation object and generating an imaging emergent beam image based on the emergent beam; the reference image determining module is used for correcting the position coordinates of the imaging emergent beam image to obtain an initial reference image; performing position matching on the initial reference image based on the treatment field to obtain a region corresponding to the treatment field in the initial reference image, and determining the region as the reference image; wherein the imaging input beam and the therapeutic input beam of the radiotherapy are same-energy-level beams.

One embodiment of the present application provides a method for acquiring a reference standard image for radiotherapy, including: determining a digital reconstructed image of the planned CT image; the planned CT image is a CT scanning image used for determining a treatment plan before treatment; obtaining an initial reference image based on the digital reconstructed image of the planned CT image and the imaged emergent beam image; and performing position matching on the initial reference image based on the treatment field to obtain a region corresponding to the treatment field in the initial reference image, and determining the region as the reference image.

One embodiment of the present application provides a system for acquiring a reference image for radiotherapy, including: the image reconstruction module is used for determining a digital reconstruction image of the planned CT image; the planned CT image is a CT scanning image used for determining a treatment plan before treatment; a registration module for obtaining an initial reference image based on the digital reconstructed image of the planned CT image and the imaged emergent beam image; and the reference benchmark image determining module is used for carrying out position matching on the initial reference benchmark image based on the treatment field, obtaining a region corresponding to the treatment field in the initial reference benchmark image, and determining the region as the reference benchmark image.

One of the embodiments of the present application provides an apparatus for acquiring a reference image for radiotherapy, wherein the apparatus at least includes a processor and at least a memory; the at least one memory is for storing computer instructions; the at least one processor is configured to execute at least some of the computer instructions to implement the method for acquiring a reference fiducial image for radiation therapy as described above.

One embodiment of the present application provides a computer-readable storage medium, which stores computer instructions, and when the computer instructions in the storage medium are read by a computer, the computer executes the method for acquiring a reference image for radiotherapy.

Drawings

The present application will be further explained by way of exemplary embodiments, which will be described in detail by way of the accompanying drawings. These embodiments are not intended to be limiting, and in these embodiments like numerals are used to indicate like structures, wherein:

FIG. 1 is a schematic view of an application scenario of a radiation therapy system according to some embodiments of the present application;

FIG. 2 is an exemplary diagram illustrating hardware and/or software components of an exemplary computing device in which a processing device may be implemented according to some embodiments of the present application;

FIG. 3 is a block diagram of a radiation treatment exit beam monitoring system according to some embodiments of the present application;

FIG. 4A is an exemplary flow chart of a method of determining a reference base image according to some embodiments of the present application;

FIG. 4B is an exemplary flow chart of another method of determining a reference base image according to some embodiments of the present application;

FIG. 5 is an exemplary illustration of imaging isocenter and planning isocenter offset, according to some embodiments of the present application;

FIG. 6 is an exemplary diagram illustrating a conversion of a three-dimensional correction to a two-dimensional imaging projection at a gantry angle of 30 according to some embodiments of the present application;

FIG. 7 is an exemplary schematic diagram illustrating collimator angle correction of an initial imaged exit beam image according to some embodiments of the present application;

FIG. 8 is an exemplary flow chart of a method of determining tolerance according to some embodiments of the present application;

FIG. 9 is an exemplary flow chart of a radiation therapy exit beam monitoring method according to some embodiments of the present application;

FIG. 10A is a comparison of a validation experiment of radiation therapy exit beam monitoring with phantom body weight change according to some embodiments of the present application;

FIG. 10B is a comparison of a validation experiment of radiation therapy exit beam monitoring with changes in the internal anatomy of a phantom according to some embodiments of the present application;

figure 10C is a comparison of a validation experiment of radiation treatment exit beam monitoring with varying degrees of error in phantom positioning according to some embodiments of the present application.

Detailed Description

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings used in the description of the embodiments will be briefly introduced below. It is obvious that the drawings in the following description are only examples or embodiments of the application, from which the application can also be applied to other similar scenarios without inventive effort for a person skilled in the art. Unless otherwise apparent from the context, or otherwise indicated, like reference numbers in the figures refer to the same structure or operation.

It should be understood that "system", "device", "unit" and/or "module" as used herein is a method for distinguishing different components, elements, parts, portions or assemblies at different levels. However, other words may be substituted by other expressions if they accomplish the same purpose.

As used in this application and the appended claims, the terms "a," "an," "the," and/or "the" are not intended to be inclusive in the singular, but rather are intended to be inclusive in the plural unless the context clearly dictates otherwise. In general, the terms "comprises" and "comprising" merely indicate that steps and elements are included which are explicitly identified, that the steps and elements do not form an exclusive list, and that a method or apparatus may include other steps or elements.

Flow charts are used herein to illustrate operations performed by systems according to embodiments of the present application. It should be understood that the preceding or following operations are not necessarily performed in the exact order in which they are performed. Rather, the various steps may be processed in reverse order or simultaneously. Meanwhile, other operations may be added to the processes, or a certain step or several steps of operations may be removed from the processes.

Fig. 1 is a schematic view of an application scenario of a radiation therapy system according to some embodiments of the present invention. As shown in fig. 1, radiation therapy system 100 includes radiation therapy device 110, network 120, one or more terminals 130, processing device 140, and storage device 150.

The radiation therapy device 110 can deliver a beam of radiation to a target object (e.g., a patient or phantom). In some embodiments, the radiation therapy device 110 can include a linear accelerator-111. Linac 111 may generate and emit a radiation beam (e.g., an X-ray beam) from treatment head 112. The radiation beam may pass through one or more specially shaped collimators (e.g., a multi-leaf grating) and be delivered to a target object. In some embodiments, the radiation beam may comprise electrons, photons, or any other type of radiation. In some embodiments, the radiation beam exhibits an energy in the megavolt range (i.e., >1MeV), and thus may be referred to as a megavolt radiation beam. The treatment head 112 may be mounted in coupling relation to the frame 113. The gantry 113 can rotate, for example, clockwise or counterclockwise about a gantry axis 114. The treatment head 112 may rotate with the gantry 113. In some embodiments, the radiation therapy device 110 can include an imaging assembly 115. The imaging assembly 115 may receive a beam of radiation that traverses a target object and may acquire projection images of a patient during radiation therapy or during imaging before and after radiation therapy, or may acquire projection images of a phantom during calibration. The radiation therapy system 100 can monitor the dose distribution during treatment through the treatment emergent beam image acquired by the imaging component 115, and ensure that the actual treatment dose distribution meets the requirements of the treatment plan and the error of the actual treatment dose distribution is within an allowable range. The imaging component 115 may include an analog detector, a digital detector, or any combination thereof. The imaging assembly 115 may be attached to the frame 113 in any manner, including an expandable and telescoping housing. Accordingly, the rotating gantry 113 can cause the treatment head 112 and the imaging assembly 115 to rotate in synchronization. In some embodiments, the radiation therapy device 110 can also include a table. The table 116 may support the patient during radiation treatment or imaging, and/or support the phantom during calibration of the radiation treatment device 110. The workstation can adjust according to the application scene of difference, for example the workstation can be followed X direction (patient left and right sides direction) and Y direction (patient back and abdomen direction) translation, moves along Z direction (patient foot head direction) business turn over. In practical applications, the directions of X, Y and Z may be different for different devices, and the definitions of X, Y and Z are not limited to the aforementioned manners. In some embodiments, prior to radiation treatment, a planned CT (Computed Tomography) scan of the patient may be performed with kilovolt energy level radiation to acquire an image of the patient's anatomy (or referred to as a localized CT image), and a treatment plan for the patient may be determined by a simulated calculation of the dose distribution of the anatomical image to the patient and the design of the radiation treatment plan. In some embodiments, before each actual treatment, the radiotherapy device 110 may be used to scan the patient to obtain multi-angle imaging emergent beam images, obtain a three-dimensional treatment guiding image based on the multiple imaging emergent beam images, match the three-dimensional treatment guiding image with the planned CT image, and correct the isocenter position of the radiotherapy device 110. In some embodiments, the reference image may be derived based on a first imaged emergent beam image. And acquiring a treatment emergent beam image based on the treatment emergent beam during the treatment process, and comparing the treatment emergent beam image with a reference image to monitor the treatment emergent beam dosage.

Network 120 may include any suitable network capable of facilitating information and/or data exchange for radiation treatment system 100. In some embodiments, one or more components of the radiation therapy system 100 (e.g., the radiation therapy device 110, the terminal 130, the processing device 140, the storage device 150, etc.) may exchange information and/or data with one or more components of the radiation therapy system 100 via the network 120. For example, the processing device 140 may obtain Planning data from a Treatment Planning System (TPS) or the storage device 150 via the network 120. Processing device 140 may acquire the imaged emergent beam image via network 120 to obtain a reference image. The processing device 140 may also directly acquire a reference image through the network 120, and match the treatment emergent beam image acquired in real time with the reference image to monitor whether the dose distribution of the actual treatment emergent beam meets the planning requirement. The network 120 may include one or more of a public network (e.g., the internet), a private network (e.g., a Local Area Network (LAN), a Wide Area Network (WAN)), etc.), a wired network (e.g., ethernet), a wireless network (e.g., an 802.11 network, a wireless Wi-Fi network, etc.), a cellular network (e.g., a Long Term Evolution (LTE) network), a frame relay network, a Virtual Private Network (VPN), a satellite network, a telephone network, a router, a hub, a server computer, etc. For example, netsNetwork 120 may include a wireline network, a fiber optic network, a telecommunications network, a local area network, a Wireless Local Area Network (WLAN), a Metropolitan Area Network (MAN), a Public Switched Telephone Network (PSTN), Bluetooth, or a network-wide network^TMNetwork, ZigBee^TMNetwork, Near Field Communication (NFC) network, and the like. In some embodiments, network 120 may include one or more network access points. For example, the network 120 may include wired and/or wireless network access points, such as base stations and/or internet exchange points, through which one or more components of the radiation therapy system 100 may connect to the network 120 to exchange data and/or information.

The terminal 130 may include a mobile device 131, a tablet computer 132, a notebook computer 133, and the like, or any combination thereof. In some embodiments, the mobile device 131 may include smart home devices, wearable devices, mobile devices, virtual reality devices, augmented reality devices, and the like, or any combination thereof. In some embodiments, the smart home devices may include smart lighting devices, smart appliance control devices, smart monitoring devices, smart televisions, smart cameras, interphones, and the like, or any combination thereof. In some embodiments, the wearable device may include a bracelet, footwear, glasses, helmet, watch, clothing, backpack, smart accessory, and the like, or any combination thereof. In some embodiments, the mobile device may comprise a mobile phone, a Personal Digital Assistant (PDA), a gaming device, a navigation device, a POS device, a laptop, a tablet, a desktop, or the like, or any combination thereof. In some embodiments, the virtual reality device and/or augmented reality device may include a virtual reality helmet, virtual reality glasses, a virtual reality patch, an augmented reality helmet, augmented reality glasses, an augmented reality patch, and the like, or any combination thereof. For example, the virtual reality device and/or augmented reality device may include a Google Glass^TM、Oculus Rift^TM、HoloLens^TMOr Gear VR^TMAnd the like. In some embodiments, the terminal 130 may be part of the processing engine 140.

The processing device 140 may process data and/or information obtained from the radiation therapy device 110, the terminal 130, and/or the storage device 150. For example, the processing device 140 may process the treatment plan data and determine motion parameters for controlling the motion of the various components of the radiation treatment device 110. Before treatment, the processing device 140 may match the planning data based on the imaged exit beam image to correct the isocenter of the treatment device 110. The processing device 140 may also determine a reasonable tolerance value for the treatment exit beam dose difference based on the simulation experiment data and monitor the actual treatment exit beam dose based on the tolerance value. In some embodiments, the processing device 140 may be a single server or a group of servers. The server group may be centralized or distributed. In some embodiments, the processing device 140 may be local or remote. For example, the processing device 140 may access information and/or data from the radiation therapy device 110, the terminal 130, and/or the storage device 150 via the network 120. As another example, the processing device 140 may be directly connected to the radiation therapy device 110, the terminal 130, and/or the storage device 150 to access information and/or data. In some embodiments, the processing device 140 may be integrated in the radiation therapy device 110. In some embodiments, the processing device 140 may be implemented on a cloud platform. For example, the cloud platform may include one or a combination of private cloud, public cloud, hybrid cloud, community cloud, distributed cloud, cross-cloud, multi-cloud, and the like. In some embodiments, the processing device 140 may be implemented by a computing apparatus 200 having one or more components as described in fig. 2.

Storage device 150 may store data, instructions, and/or any other information. In some embodiments, storage device 150 may store data obtained from processing device 140 and/or terminal 130. Such as treatment planning data, imaged exit beam projection images, reference fiducial images, tolerance values, etc. In some embodiments, storage device 150 may store data and/or instructions that processing device 140 may execute or use to perform the example methods described herein. In some embodiments, the storage device 150 may include one or a combination of mass storage, removable storage, volatile read-write memory, read-only memory (ROM), and the like. Mass storage may include magnetic disks, optical disks, solid state drives, removable storage, and the like. The removable memory may include a flash drive, floppy disk, optical disk, memory card, ZIP disk, magnetic tape, or the like. The volatile read and write memory may include Random Access Memory (RAM). The RAM may include Dynamic Random Access Memory (DRAM), double data rate synchronous dynamic random access memory (DDR-SDRAM), Static Random Access Memory (SRAM), silicon controlled random access memory (T-RAM), zero capacitance random access memory (Z-RAM), and the like. The ROM may include mask read-only memory (MROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), compact disc read-only memory (CD-ROM), optical discs such as digital versatile discs, and the like. In some embodiments, the storage device 150 may be implemented by a cloud platform as described herein. For example, the cloud platform may include one or a combination of private cloud, public cloud, hybrid cloud, community cloud, distributed cloud, cross-cloud, multi-cloud, and the like.

In some embodiments, the storage device 150 may be connected to the network 120 to enable communication with one or more components (e.g., processing device 140, terminal 130, etc.) in the radiation therapy system 100. One or more components in radiation treatment system 100 may read data or instructions in storage device 150 through network 120. In some embodiments, the storage device 150 may be part of the processing device 140.

Fig. 2 is an exemplary diagram illustrating hardware and/or software components of an exemplary computing device 200 that may implement processing device 140 according to some embodiments of the invention. As shown in FIG. 2, computing device 200 may include a processor 210, memory 220, input/output (I/O)230, and communication ports 240.

The processor 210 may execute computer instructions (e.g., program code) and may perform the functions of the processing device 140 according to the techniques described in the application. The computer instructions may be used to perform particular functions described herein and may include, for example, programs, objects, components, data structures, programs, modules, and functions. For example, the processor 210 may process planning data acquired from the storage device 150, and/or any other component of the radiation therapy system 100. In some embodiments, processor 210 may include one or more hardware processors, such as microcontrollers, microprocessors, Reduced Instruction Set Computers (RISC), Application Specific Integrated Circuits (ASICs), application specific instruction set processors (ASIPs), Central Processing Units (CPUs), Graphics Processing Units (GPUs), Physical Processing Units (PPUs), Digital Signal Processors (DSPs), Field Programmable Gate Arrays (FPGAs), advanced RISC machines (advanced RISCs), Programmable Logic Devices (PLDs), any circuit or combination of several that is capable of executing one or more functions.

For illustration only, only one processor is depicted in computing device 200. However, it should be noted that the computing device 200 may also include multiple processors. Operations and/or methods described herein as being performed by one processor may also be performed jointly or separately by multiple processors. For example, if the processors of the computing device 200 described in this application perform operations a and B, it should be understood that operations a and B may also be performed jointly or separately by two or more different processors in the computing device 200 (e.g., a first processor performing operation a and a second processor performing operation B, or a first processor and a second processor performing operations a and B together).

The memory 220 may store data/information acquired from the radiation treatment device 110, the terminal 130, the storage device 150, and/or any other component of the radiation treatment system 100. In some embodiments, the memory 220 may include one or a combination of mass storage, removable storage, volatile read-write memory, read-only memory (ROM), and the like. Mass storage may include magnetic disks, optical disks, solid state drives, removable storage, and the like. The removable memory may include a flash drive, floppy disk, optical disk, memory card, ZIP disk, magnetic tape, or the like. The volatile read and write memory may include Random Access Memory (RAM). The RAM may include Dynamic Random Access Memory (DRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), Static Random Access Memory (SRAM), silicon controlled random access memory (t-RAM), zero capacitance random access memory (Z-RAM), and the like. The ROM may include mask read-only memory (MROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), compact disc read-only memory (CD-ROM), optical discs such as digital versatile discs, and the like. In some embodiments, memory 220 may store one or more programs and/or instructions for performing the example methods described herein. For example, the storage 220 may store a program that may be used by the processing device 140 to determine a motion parameter for a plurality of components.

Input/output 230 may input and/or output signals, data, information, and the like. In some embodiments, the input/output 230 may enable interaction between a user and the processing device 140. In some embodiments, input/output 230 may include an input device and an output device. The input device may include one or a combination of a keyboard, a mouse, a touch screen, a microphone, and the like. The output device may include one or a combination of a display device, a speaker, a printer, a projector, and the like. The display device may include one or a combination of Liquid Crystal Display (LCD), Light Emitting Diode (LED) display, flat panel display, arc screen, television device, Cathode Ray Tube (CRT), touch screen, and the like.

The communication port 240 may connect to a network (e.g., network 120) to facilitate data communication. The communication port 240 may establish a connection between the processing device 140 and the radiation treatment device 110, the terminal 130, and/or the storage device 150. The connection may be one or a combination of a wired connection, a wireless connection, any connection capable of data transmission and/or reception, and the like. The wired connection may include, for example, one or a combination of electrical cables, optical cables, telephone lines, and the like. The wireless connection may comprise, for example, Bluetooth^TMLink, Wi-Fi^TMLink, WiMAX^TMLink, wireless local area network link, ZigBee^TMLink, mobile network link (e.g., 3G, 4G, 5G, etc.), or a combination thereof. In some embodiments, the communication port 240 may be and/or include a standardized communication port, such as RS232, RS485, and the like. In some embodiments, the communication port 240 may be a specially designed communication port. For example, the communication port 240 may be designed in accordance with digital imaging and communications in the medical (DICOM) protocol.

Fig. 3 is a block diagram of a radiation treatment exit beam monitoring system according to some embodiments of the present application. As shown in fig. 3, the radiation therapy exit beam monitoring system may include an acquisition module 310, a determination module 320, an execution module 330, and a reference fiducial image determination module 340.

The acquisition module 310 may be used to acquire real-time treatment exit beam images. In some embodiments, the real-time treatment exit beam image may be generated based on exit beams obtained by the treatment input beam through the irradiation subject during the current radiation treatment procedure. In some embodiments, the treatment input beam may pass through one or more collimators having a particular shape to form a beam having a cross-sectional shape that is less than or equal to the shape of the patient's tumor. In some embodiments, the treatment device may include an imaging assembly that may receive an exit beam of the treatment input beam through the irradiation target, forming a treatment exit beam projection image. In some embodiments, the imaging assembly may acquire the treatment exit beam projection images at a frequency. In some embodiments, the acquisition module 310 is configured to acquire a reference baseline image. The reference image may be determined based on an imaged emergent beam image generated based on an emergent beam obtained by the imaged incident beam through the radiating object. In some embodiments, the reference image may be determined based on the first-time imaged exit beam image, which facilitates monitoring of changes in exit beam dose based on the reference image when the patient's own weight or tissue changes. In some embodiments, the imaged exit beam image may be an exit beam projection image of the imaged incident beam through the radiating object. In some embodiments, the imaging input beam is a same energy level beam as a therapeutic input beam of radiation therapy. For example, both beams are beams of megavolt energy. In some embodiments, the imaging input beam and the therapy input beam are from the same radiation source. For example, the imaging input beam and the therapy input beam are generated by the same accelerator. In some embodiments, the imaging input beam and the therapy input beam may be spectrally identical beams. For example, the imaging input Beam and the treatment input Beam may originate from different radiation sources, and the imaging radiation source and the treatment radiation source may be first Beam matched (Beam match) to adjust the imaging input Beam and the treatment input Beam to be beams of the same energy spectrum. In some embodiments, homography may be understood as a range in which the beam spectral profiles of the imaging input beam and the therapy input beam are substantially the same. In some embodiments, the imaging exit beam image is acquired prior to radiation therapy. In some embodiments, the imaged exit beam image is an image used for image-guided user positioning prior to radiation treatment. In some embodiments, the imaging CT scan may be a CBCT (Cone Beam Computed Tomography) scan, resulting in a two-dimensional imaged exit Beam image. In some embodiments, a plurality of imaging emergent beam images can be obtained at a plurality of projection angles, and the imaging emergent beam images at the plurality of angles are subjected to simulated reconstruction to obtain tomography, so that the tomography is subjected to positioning matching with a planned CT image.

The determination module 320 may be configured to determine whether a difference in pixel values between the real-time treatment exit beam image and the reference image satisfies a preset condition based on the real-time treatment exit beam image and the reference image. In some embodiments, a ratio of pixel values of corresponding pixel points may be determined based on the real-time treatment exit beam image and the reference image. Since the imaging beam and the treatment beam are rays of the same energy level, only the dose rate of the imaging beam and the dose rate of the treatment beam are different. In an ideal case, the pixel ratio of the imaged exit beam image and the therapeutic exit beam image should be constant. And ideally the ratio should be the ratio of the imaging dose rate to the treatment plan dose rate. Based on such a principle, a reference image is established based on the first-imaged emergent beam image, and the treatment emergent beam can be monitored. In some embodiments, it may be determined whether the pixel value difference is within a tolerance range based on the pixel value ratio. In some embodiments, the tolerance range is a reasonable fluctuation range of the ratio determined based on a combination of one or more of signal-to-noise ratio, output factor, penumbra position, non-uniform ray effects, or device stability factors. In some embodiments, where the signal-to-noise ratio is the ratio of exit beam dose signal to noise, differences in imaging and treatment field doses may directly result in fluctuations in the pixel ratio of the treatment exit beam image and the imaged exit beam image. In some embodiments, the output factor is a relationship between an absorbed dose at a point on a central axis of the in vivo beam and a field size. The size of the field of the treatment plan is different from that of the imaging field, and the output factors are different, so that the fluctuation of the pixel value ratio is increased. In some embodiments, the boundary of the treatment field is generally less than or equal to the tumor shape, which typically requires multiple gratings to mask to form a precise irregular boundary. Due to other factors such as a ray source and a collimation system, the boundary of a treatment field is blurred, and a certain proportion of penumbra position areas are formed on the boundary. The pixel ratio of the treatment emergent beam image to the imaging emergent beam image in the penumbra position area is difficult to be a constant, and large dose error exists. In some embodiments, the rays within the field are generally non-uniform, and non-uniformity of the rays can lead to dose errors. For example, a shift in the treatment isocenter can cause the dose peak to shift, creating a dose error. In some embodiments, equipment stability factors may include control accuracy, equipment operating conditions, whether maintenance is appropriate, etc. factors of the equipment itself. In some embodiments, simulation experiments may be performed based on the phantom to derive simulated ratios of the treatment exit beam image and the reference fiducial image. In some embodiments, a tolerance range may be determined based on the simulated ratio. In some embodiments, simulation modeling may be performed according to a treatment plan using simulated phantoms. The phantom may be a simulated phantom of the human body at various ages and on various parts of the human body. In some embodiments, simulation experiments may be repeated using different phantoms to obtain simulated ratios of the plurality of treatment exit beam images and the reference image, and comparing the plurality of simulated ratios to determine a tolerance range.

The execution module 330 may be configured to control the radiation therapy process based on the determination result. In some embodiments, when the difference in pixel values of the real-time treatment exit beam image and the reference image is outside the tolerance range, the current treatment is stopped. In some embodiments, a combination of one or more of aging of the apparatus, failure of the apparatus, errors in the radiation therapy system, weight changes in the patient, tissue changes, organ changes in the patient's breathing or other body movements during treatment, or body shifts in the patient over time may cause the treatment emergent beam dose error to be large and out of tolerance. If the ratio of the pixel values of the real-time treatment emergent beam image and the reference image exceeds the tolerance range, the treatment emergent beam is probably not in accordance with the planned requirement, the dose distribution of the treatment emergent beam can be seriously deviated from the planned position, and the tissue or organ in the non-tumor area can be damaged. Or the dose rate of the radiation does not meet the plan requirements, and the treatment effect is influenced. At this time, the radiation therapy can be stopped, and the factors causing the difference to exceed the tolerance range can be determined or eliminated, so that the radiation therapy effect is ensured, and unnecessary damage to the patient is avoided.

The reference image determining module 340 may be configured to perform position coordinate correction on the imaged emergent beam image to obtain an initial reference image. In some embodiments, an imaging isocenter position and a treatment plan isocenter position may be obtained, and the imaged exit beam image is position coordinate corrected based on a difference between the imaging isocenter position and the treatment plan isocenter position. In some embodiments, prior to each treatment, a plurality of angular imaging MV-CBCT scans may be performed on the patient, and a three-dimensional imaging image may be reconstructed from the plurality of angular imaging exit beam images. In some embodiments, the three-dimensional imaging image may be compared with a planned three-dimensional CT image reflecting the anatomical structure to determine a three-dimensional position offset between the imaging isocenter and the planned isocenter in the current three-dimensional space, and a reverse displacement of the three-dimensional position offset is a three-dimensional correction of the imaging isocenter. In some embodiments, a three-dimensional correction between the imaging isocenter and the planning isocenter may be converted to a two-dimensional correction, and the two-dimensional MV-CBCT imaging exit beam image may be positionally corrected to match the imaging exit beam image with the planned anatomical image, resulting in an initial reference image.

In some embodiments, the reference baseline image determination module 340 may be used to perform collimator rotation angle correction on the initial reference baseline image. In some embodiments, an angle of a collimator at the time of imaging and a collimator angle of a treatment plan may be acquired, an angular difference between the collimator angle at the time of imaging and the collimator angle of the treatment plan is determined, and the imaged exit beam image is position coordinate corrected based on the angular difference. For example, the collimator angle value in the treatment plan may be obtained, and the boundary range and the boundary shape of the initial imaging emergent beam image may be determined according to the plan collimator angle, so as to obtain the initial reference image. In some embodiments, the mask image may be rotated according to the planned collimator angle, and the mask image and the initial reference image are subjected to a pixel and operation to obtain a reference image after the boundary rotation.

In some embodiments, the reference baseline image determination module 340 may be configured to perform position matching on the initial reference baseline image based on the treatment field, obtain a region in the initial reference baseline image corresponding to the treatment field, and determine the region as the reference baseline image. In some embodiments, the mask image may be generated by simulating the position and boundary extent of the planned treatment field from the position of a multi-leaf grating (MLC) in the treatment plan. In some embodiments, the mask image may be operated on with the initial reference base image to obtain the corresponding region. In some embodiments, the pixel value of the region corresponding to the treatment field in the mask image may be set to 1, and the pixel value of the region other than the treatment field may be set to 0. And performing pixel and operation on the mask image and the initial reference image subjected to position coordinate correction, and extracting a region corresponding to the treatment field in the initial reference image to obtain a reference image. In some embodiments, at least one treatment exit beam image may be acquired, boundary information of an actual treatment field may be determined based on the treatment exit beam image, and the mask image may be validated based on the boundary information. In order to avoid the influence of the error between the actual position and the set value on the accuracy of the reference standard image, the mask image can be verified according to the boundary data of the actual multi-leaf grating in the actual treatment process so as to obtain the reference standard image which is more in line with the treatment condition. In some embodiments, at least one treatment exit beam image may be acquired during treatment, a Hough Transform (Hough Transform) may be performed on the treatment exit beam image, an actual blade position may be determined, and it may be verified whether the actual grating position is in place according to the treatment plan based on the grating position in the treatment plan.

It should be understood that the system and its modules shown in FIG. 3 may be implemented in a variety of ways. For example, in some embodiments, the system and its modules may be implemented in hardware, software, or a combination of software and hardware. Wherein the hardware portion may be implemented using dedicated logic; the software portions may be stored in a memory for execution by a suitable instruction execution system, such as a microprocessor or specially designed hardware. Those skilled in the art will appreciate that the methods and systems described above may be implemented using computer executable instructions and/or embodied in processor control code, such code being provided, for example, on a carrier medium such as a diskette, CD-or DVD-ROM, a programmable memory such as read-only memory (firmware), or a data carrier such as an optical or electronic signal carrier. The system and its modules of the present application may be implemented not only by hardware circuits such as very large scale integrated circuits or gate arrays, semiconductors such as logic chips, transistors, or programmable hardware devices such as field programmable gate arrays, programmable logic devices, etc., but also by software executed by various types of processors, for example, or by a combination of the above hardware circuits and software (e.g., firmware).

It should be noted that the above descriptions of the candidate item display and determination system and the modules thereof are only for convenience of description, and are not intended to limit the present application within the scope of the illustrated embodiments. It will be appreciated by those skilled in the art that, given the teachings of the present system, any combination of modules or sub-system configurations may be used to connect to other modules without departing from such teachings. For example, in some embodiments, for example, the acquiring module 310, the determining module 320, the executing module 330 and the reference image determining module 340 disclosed in fig. 3 may be different modules in a system, or may be a module that implements the functions of two or more modules described above. For example, the determination module 320 and the reference image determination module 340 may be two modules, or one module may have both transmitting and receiving functions. For example, each module may share one memory module, and each module may have its own memory module. Such variations are within the scope of the present application.

FIG. 4A is an exemplary flow chart of a method of determining a reference base image according to some embodiments of the present application. Flow 400 may be performed by processing logic that may comprise hardware (e.g., circuitry, dedicated logic, programmable logic, microcode, etc.), software (instructions run on a processing device to perform hardware simulation), etc., or any combination thereof.

At step 410, the position coordinates of the imaged emergent beam image may be corrected to obtain an initial reference image. In some embodiments, step 410 may be performed by the reference base image determination module 340. In some embodiments, the imaged exit beam image may be an exit beam projection image of the imaged incident beam through the radiating object. In some embodiments, the imaged exit beam image may be position coordinate corrected according to the treatment plan.

In some embodiments, the imaged exit beam image may be obtained by imaging the patient with a radiotherapy device prior to radiotherapy. Wherein the imaging input beam may be the same energy level beam as the therapy input beam. In some embodiments, the treatment input beam may be a megavolt input beam and the imaging input beam is also a megavolt input beam. For example, the energy of the imaging input beam may be 6MV and the energy of the therapeutic input beam may be 6 MV. In some embodiments, the imaging input beam may be from the same source as the therapy input beam. For example, the imaging input beam and the therapy input beam are generated by the same accelerator. In some embodiments, the imaging input beam and the therapy input beam are spectrally identical beams. For example, the imaging input Beam and the treatment input Beam may originate from different radiation sources, and the imaging radiation source and the treatment radiation source may be first Beam matched (Beam match) so that the imaging input Beam and the treatment input Beam are co-spectral beams. In some embodiments, the imaging input beam and the treatment input beam are both megavoltage beams, generated by the same accelerator in the radiotherapy apparatus, and the imaging output beam image is a MV-CBCT (megavoltage CBCT) reconstructed front plane projection image. The imaging incident beam and the treatment incident beam are homoenergetic beams, a reference image can be established based on the imaging emergent beam image, and whether the dose distribution of the actual treatment emergent beam meets the planning requirement or not is monitored by applying the reference image. The reference image can be simply and accurately obtained, and the precision of radiotherapy is improved. Meanwhile, the radiation beam with the same energy level as the treatment incident radiation beam is adopted, the imaging incident beam dose and the radiotherapy dose can be integrated, the imaging dose is counted into the treatment dose, and the risk burden of an extra patient is avoided.

In some embodiments, prior to radiation therapy, a planned CT (Computed Tomography) scan of the patient may be performed to obtain an image of the patient's anatomy (otherwise known as a localized CT image). In some implementations, a planned CT scan of a phantom simulating a patient may also be performed to acquire an image of the patient's anatomy. The treatment plan for the patient is determined by simulated calculation of dose distribution for the patient from the anatomical map and planning of the radiotherapy plan. In some embodiments, the treatment plan may include an image of the anatomy of the patient (otherwise known as a scout CT image), a dose distribution determined from the anatomical image, and treatment plan parameters. In some embodiments, the treatment plan parameters may include one or a combination of data including isocenter position of the treatment plan, collimator angle of the treatment plan, and position data of the gratings. In some embodiments, the collimator angle may be the angle of rotation of the collimator to change the direction of movement of the multi-leaf grating, the collimator angle being adjusted with the multi-leaf grating position to form the desired field shape to block non-tumor area rays. In some embodiments, a localized CT image may be obtained by scanning a radiation object with a kilovolt energy level beam, such as a radiation target using a CT device. In some embodiments, the scout CT images may be three-dimensional tomographic images.

In some embodiments, the imaged exit beam image may be corrected for positional coordinates based on the localized CT image in the treatment plan. In some embodiments, the patient is subjected to a multi-angle imaging scan using a radiation therapy device prior to radiation therapy, wherein the imaging scanning beam is a megavolt energy level beam that is at the same energy level as the therapy beam, and further wherein the imaging scanning beam and the therapy beam can be from the same radiation source, or the imaging scanning beam and the therapy beam can be a co-spectral radiation source. And performing three-dimensional reconstruction on the projection data obtained by scanning to obtain a three-dimensional treatment guide image, and matching the three-dimensional treatment guide image with the positioning CT image to obtain positioning errors in the X direction (the left and right directions of the patient), the Y direction (the back and abdomen direction of the patient) and the Z direction (the foot and head direction of the patient). In some embodiments, the imaging CT scan may be a CBCT (Cone Beam Computed Tomography) scan, which may result in a series of two-dimensional imaging exit Beam images.

In some embodiments, the initial reference image may be corrected for position coordinates based on the imaged exit beam projection image having the same energy level as the therapeutic exit beam. In some embodiments, the position coordinate corrections may include isocenter corrections. As shown in fig. 1, the central axis of the treatment head 112 intersects the axis of rotation of the gantry 113 at a point, which is referred to as the isocenter. In some embodiments, the imaging isocenter position and the treatment plan isocenter position may be acquired. In some embodiments, prior to each treatment, the patient may be subjected to a multi-angle imaging MV-CBCT scan, and a pilot treatment image reconstructed from the multi-angle imaging exit beam images. In some embodiments, the localized CT images in the treatment plan may be acquired from the radiation treatment device 110, the network 120, the terminal 130, the storage device 150, or any device or component disclosed herein capable of storing data. In some embodiments, the three-dimensional imaging image may be compared with the planned three-dimensional anatomical image to obtain the imaging isocenter position and the treatment planned isocenter position, and a three-dimensional position offset between the imaging isocenter and the planning isocenter in a three-dimensional space is determined, wherein the reverse displacement of the three-dimensional position offset is a three-dimensional correction of the imaging isocenter. As shown in fig. 5, X ' Y ' Z ' is the three-dimensional anatomical image of the treatment plan, O ' is the isocenter of the three-dimensional anatomical image of the treatment plan, XYZ is the three-dimensional imaging image, and O is the isocenter of the three-dimensional imaging image, the anatomical structures in the two three-dimensional images are matched, the offset amounts of O ' and O in the X, Y and Z directions are determined, and the reverse shift value is the three-dimensional correction amount between the imaging isocenter and the planning isocenter.

In some embodiments, a three-dimensional correction between the imaging isocenter and the planning isocenter may be converted to a two-dimensional correction, and the two-dimensional MV-CBCT imaging exit beam image may be positionally corrected to match the imaging exit beam image with the planned anatomical image, resulting in an initial reference image. In some embodiments, when the gantry angle is 0 ° (the source is at 12 o 'clock position on the gantry) or 180 ° (the source is at 6 o' clock position on the gantry), the Y direction may be the ventral direction of the patient, the Y direction correction amount is the adjustment value of the height between the patient and the source, and the Y direction correction amount may be converted into a scaled-up value or a scaled-down value of the two-dimensional image for correction. The X direction may be the left-right direction of the patient, the Z direction may be the head-foot direction of the patient, the correction amounts in the X and Z directions are the translation amounts of the table 160 on the XOZ plane, and the correction amounts in the X, Z direction may be converted into two-dimensional imaging emergent beam images to perform corresponding translation components in the X, Z direction respectively for correction. For example, when the gantry angle is 0 ° (the source is at 12 positions on the gantry), the imaging projection is performed to obtain an imaging emergent beam image of 0 °. The obtained three-dimensional correction amount can be converted into a correction amount of a two-dimensional imaging projection image of 0 °. The correction value in the Y direction is a proportional enlargement value or a reduction value of the two-dimensional imaging projection image of 0 °. X, Z, the two-dimensional imaging projection image corrected by 0 ° has a translation component in the X, Z direction, respectively. For another example, as shown in FIG. 6, the source is rotated about O in the XOY plane, imaging is performed at a gantry angle of +30 (the source is angled 30 to the left at the 12 point position on the gantry), assuming a correction amount of isocenter in the three-dimensional coordinate system is (x, Y, z), where Y has a component ycos30 on Y', and the two-dimensional imaged exit beam image is scaled up or down according to ycos 30. x has a component xcos30 ° in the ZOX' plane, and the imaged emergent beam image is translated according to xcos30 ° z.

In some embodiments, the position coordinate corrections may include collimator rotation angle corrections. In general, when an imaging scan is performed, the collimator angle for imaging is set to 0 °. In the actual treatment process, the collimator needs to be set with a certain rotation angle according to the shape and size of the tumor to obtain a more ideal dose distribution. Establishing a reference image according to the imaging emergent beam image requires that the collimator angle correction is carried out on the initial imaging emergent beam image according to the treatment requirement so as to match the treatment plan, thereby achieving the purpose of accurately monitoring the treatment emergent beam. In some embodiments, collimator angle values in the treatment plan may be obtained, and the boundary range and boundary angle of the initial reference baseline image determined from the planned collimator angles. In some embodiments, the mask image may be rotated according to the planned collimator angle, and the mask image and the initial reference image are subjected to a pixel and operation to obtain a reference image after the boundary rotation. For example, as shown in fig. 7, if the collimator angle is θ in the treatment plan, the mask image may be rotated clockwise or counterclockwise on the XOZ plane by θ around the isocenter as the rotation center to match the mask image with the treatment plan, and the rotated mask image and the initial reference image may be subjected to and operation to obtain a reference image (the field of view whose boundary is a solid line) corrected by the collimator angle.

In step 420, the initial reference image may be subjected to position matching based on the treatment field, a region corresponding to the treatment field in the initial reference image is obtained, and the region is determined as the reference image.

In some embodiments, the treatment field is the field range of the emergent beam at the time of actual treatment. The treatment field is far smaller than the imaging field, and in order to protect the tissues and organs in the non-tumor area, the radiotherapy beam can pass through the multi-leaf grating, and the multi-leaf grating can block off the redundant beam to avoid the tissues in the non-tumor area from being damaged by the radiotherapy beam, and the treatment field is generally smaller than or equal to the area of the tumor. The position of each grating in the multi-leaf grating is adjustable, so that a space matched with the treatment area is formed among the gratings, and the treatment beam can conveniently pass through the space. Establishing a reference image, determining a region corresponding to the treatment field in the imaging emergent beam image, and dividing the region to be used as the reference image.

In some embodiments, the mask image may be generated by simulating the position and boundary extent of the planned treatment field from the position of a multi-leaf grating (MLC) in the treatment plan. In some embodiments, the mask image may be operated on with the initial reference base image to obtain the corresponding region. In some embodiments, the pixel value of the region corresponding to the treatment field in the mask image may be set to 1, and the pixel value of the region other than the treatment field may be set to 0. And performing pixel and operation on the mask image and the initial reference image subjected to position coordinate correction, and extracting a region corresponding to the treatment field in the initial reference image to obtain a reference image.

In some embodiments, the actual leaf position of the multi-leaf grating in the actual treatment process may deviate from the theoretical setting value, and in order to avoid the influence of the error of the actual position and the setting value on the accuracy of the reference base image, the mask image may be verified according to the boundary data of the actual multi-leaf grating in the actual treatment process to obtain a reference base image more suitable for the treatment condition. In some embodiments, at least one treatment exit beam image may be acquired during treatment, a Hough Transform (Hough Transform) may be performed on the treatment exit beam image, an actual blade position may be determined, and it may be verified whether the actual grating position is in place according to the treatment plan based on the grating position in the treatment plan.

In some embodiments, to protect the tissues and organs of the non-tumor region from the radiation beam, it is desirable to have a treatment field that can match various irregularly shaped tumors. The edges of the treatment field typically require multiple gratings to mask to form precise irregular boundaries. In general, factors such as a ray source and a collimation system cause the edge of a treatment field to be influenced by penumbra in different degrees, so that the boundary is blurred. In order to eliminate the penumbra influence as much as possible, it is necessary to eliminate the field boundary region with the serious penumbra influence in the mask image to improve the edge precision of the mask image, so as to obtain a reference image with higher accuracy and reduce the influence of the penumbra region on the treatment emergent beam monitoring. In some embodiments, regions with more severe treatment field boundary penumbra effects can be eliminated by an open operation. The open operation is to erode first and then expand. Erosion is a process of eliminating boundary points and shrinking the boundary toward the inside of the region, and can be used to eliminate the boundary region where the boundary is slightly susceptible to penumbra. Dilation is a process of merging all background points in contact with an object into the object, expanding the boundary outside the region, and can be used to fill up the holes in the eliminated region of the boundary region. In some embodiments, the mask image corrected by the on operation and the initial reference image are subjected to a pixel and operation to obtain a reference image.

FIG. 4B is an exemplary flow chart of another method of determining a reference base image according to some embodiments of the present application. Flow 500 may be performed by processing logic that may comprise hardware (e.g., circuitry, dedicated logic, programmable logic, microcode, etc.), software (instructions run on a processing device to perform hardware simulation), etc., or any combination thereof.

At step 510, a digitally reconstructed image (DRR) of the planning CT image may be first determined. In some embodiments, the planned CT image is a pre-treatment CT scan image used to determine a treatment plan, and as previously described, an image of the patient's anatomy (otherwise known as a scout CT image) may be acquired. In some embodiments, the digitally reconstructed image of the planned CT image may be a two-dimensional projection reconstructed from a three-dimensional tomographic image of the planned CTAnd (4) an image. In some embodiments, may be according to S₀Exp (- μ L) calculates a plurality of projection data, and determines a digitally reconstructed image of the planned CT image based on the plurality of projection data. Wherein S is₀And subtracting a background value from the null-scan signal, wherein the null-scan signal is a signal collected by the detector when rays are only attenuated in the air, and the background value is an environmental signal collected by the detector when the radioactive source does not work. L is the length in the body in the linear distance between the detector and the planned CT radiation source. In some embodiments, the linear distance between the detector and the planned CT radiation source may be a linear distance between a detection unit located at an intermediate position on the detector and the radiation source. μ is the average attenuation coefficient of a ray traversing the body from one direction. In some embodiments, the attenuation coefficient μmay be calculated from the CT pixel values. In some embodiments, the attenuation coefficient may be an average of the attenuation coefficients of all pixels through which radiation passes through the portion of the human body.

An initial reference image may be derived based on the digitally reconstructed image of the planned CT image and the imaged exit beam image, step 520. In some embodiments, the initial reference image may be obtained by deformation registration of the digitally reconstructed image of the planned CT and the imaged exit beam image based on an image registration algorithm.

In some embodiments, an MVCBCT projection image may be acquired. In some embodiments, the MVCBCT projection image may be an outgoing beam projection image obtained by imaging an incoming beam through a radiating object. In some embodiments, the imaged exit beam image may be obtained by imaging the patient with the radiotherapy apparatus prior to the first radiation treatment. Wherein the imaging input beam may be the same energy level beam as the therapy input beam. For example, the treatment input beam may be a megavolt input beam and the imaging input beam may also be a megavolt input beam. In some embodiments, the imaging input beam may be from the same source as the therapy input beam. For example, the imaging input beam and the therapy input beam are generated by the same accelerator. In some embodiments, the imaging input beam and the therapy input beam are spectrally identical beams. For example, the imaging input Beam and the treatment input Beam may originate from different radiation sources, and the imaging radiation source and the treatment radiation source may be first Beam matched (Beam match) so that the imaging input Beam and the treatment input Beam are co-spectral beams. In some embodiments, the imaging input beam and the treatment input beam are both megavoltage beams, generated by the same accelerator in the radiotherapy apparatus, and the imaging output beam image is a MV-CBCT (megavoltage CBCT) reconstructed front plane projection image. The imaging incident beam and the treatment incident beam are homoenergetic beams, a reference image can be established based on the imaging emergent beam image, and whether the dose distribution of the actual treatment emergent beam meets the planning requirement or not is monitored by applying the reference image. The reference image can be simply and accurately obtained, and the precision of radiotherapy is improved. Meanwhile, the radiation beam with the same energy level as the treatment incident radiation beam is adopted, the imaging incident beam dose and the radiotherapy dose can be integrated, the imaging dose is counted into the treatment dose, and the risk burden of an extra patient is avoided.

In some embodiments, the registration algorithm may include one or a combination of feature point registration algorithm, Demons algorithm, B-spline mutual information algorithm, finite element analysis, and the like. For example, taking the feature point registration algorithm as an example, the imaged emergent beam image may be used as a floating image, the digital reconstructed image of the planned CT may be used as a reference image, feature information of the floating image and the reference image, such as feature parameters such as feature point coordinates, feature point gray-scale values, and attenuation coefficients, is extracted, and registration calculation of the feature points is performed according to the registration algorithm, so as to obtain a fused image of the imaged emergent beam image and the planned CT image. And taking the fused image as an initial reference image. The initial reference image established by the method of the embodiment can convert the kilovolt-level planning CT image into the megavolt-level initial reference image, and the most original and basic anatomical structure information and attenuation information are retained to the maximum extent, so that the subsequent treatment emergent beam monitoring is more accurate.

In step 530, the initial reference image may be subjected to position matching based on the treatment field, a region corresponding to the treatment field in the initial reference image is obtained, and the region is determined as the reference image. Step 530 is the same as step 420 in the process 400, and the detailed description refers to the related description of step 420.

FIG. 8 is an exemplary flow chart of a method of determining tolerance according to some embodiments of the present application. Flow 800 may be performed by processing logic that may comprise hardware (e.g., circuitry, dedicated logic, programmable logic, microcode, etc.), software (instructions run on a processing device to perform hardware simulation), etc., or any combination thereof.

At step 810, a simulation experiment may be performed based on the treatment plan to obtain a simulated ratio of the treatment exit beam image and the reference fiducial image. In some embodiments, step 810 may be performed by decision module 320. If the imaging beam and the treatment beam are radiation of the same energy level, only the dose rate of the imaging beam and the dose rate of the treatment beam are different. The difference in dose rate may be embodied as a difference in pixel values of the outgoing beam image. The ratio of the pixel values of the imaging emergent beam image and the therapeutic emergent beam image is approximate to the ratio of the dose rates of the imaging beam and the therapeutic beam in the same region (after the response of the dose rate of the detector is corrected). Therefore, in an ideal case, the pixel ratio of the imaged exit beam image and the therapeutic exit beam image on the same area should be constant. And ideally the ratio should be the ratio of the imaging dose rate to the treatment plan dose rate. Based on such principles, a reference image is established based on the imaged emergent beam image, and the treatment emergent beam can be monitored. If the pixel ratio of the treatment emergent beam image to the reference image is close to the theoretical value and fluctuates in a reasonable interval, the dose distribution of the treatment emergent beam meets the plan requirement, and the reasonable fluctuation range is the monitoring tolerance. In some embodiments, the factors affecting tolerance may include one or a combination of signal-to-noise ratio, output factor, penumbra position, non-uniform ray effect, or device stability factor, among others. In some embodiments, the signal-to-noise ratio is the ratio of the exit beam dose signal to noise, and differences in imaging dose and treatment dose may directly result in differences in pixel ratio of the treated exit beam image and the imaged exit beam image. In some embodiments, the output factor is a relationship between an absorbed dose at a point on a central axis of the in vivo beam and a field size. The size of the field of the treatment plan is different from that of the imaging field, and the output factors are different, so that the fluctuation of the pixel value ratio is increased. In some embodiments, the boundary of the treatment field is generally less than or equal to the tumor shape, so the edge of the treatment field typically requires multiple gratings to mask to form a precise irregular boundary. The boundary of the treatment field is blurred, and a certain proportion of penumbra position areas exist on the boundary. In the penumbra position area, the pixel ratio of the treatment emergent beam image to the imaging emergent beam image is difficult to be a constant and has larger error. When the mask image is determined, the boundary with a large penumbra position proportion is deducted to reduce the error of the pixel ratio caused by the penumbra position area. However, the existence of the penumbra position area still generates a certain system error. In some embodiments, the radiation within the field is generally non-uniform, the dose rate for the radiation at the center may be higher, the dose rate for the radiation near the edges of the field may be lower, and a peak may appear in the middle of the radiation. Non-uniformity of the radiation can lead to dose errors. For example, a shift in the treatment isocenter can cause the dose peak to shift, creating a dose error. In some embodiments, in order to reduce the influence of ray non-uniformity, the imaging emergent beam image and the treatment emergent beam image formed by the uniform ray can be obtained by using an idle-scan image formed by a maximum field passing through the air on the two-dimensional detector as a denominator to respectively remove the imaging emergent beam image and the treatment emergent beam image formed by the uniform ray, the imaging emergent beam image formed by the uniform ray is corrected in position coordinates and then is established as a reference image, and the treatment emergent beam image formed by the uniform ray is compared with the reference image to calculate a pixel value so as to eliminate the influence of the non-uniform ray. In some embodiments, equipment stability factors may include control accuracy, equipment operating conditions, whether maintenance is appropriate, etc. factors of the equipment itself.

In some embodiments, simulation modeling may be performed according to a treatment plan using simulated phantoms. The phantom may be a simulated phantom of the human body at various ages and on various parts of the human body. In some embodiments, the mold body may be a highly repeatable rigid mold body. In some embodiments, simulation experiments may be repeated using different phantoms to obtain simulated ratios of the plurality of treatment exit beam images and the reference image, and comparing the plurality of simulated ratios to determine a tolerance range. In some embodiments, the simulation experiment may be a simulation treatment using a phantom according to a treatment plan, acquiring an imaged emergent beam image, establishing a reference image based on the imaged emergent beam image, and comparing the acquired treated emergent beam image with the reference image to obtain a pixel ratio. Simulation treatment can be performed using different phantoms to obtain pixel ratios of the plurality of treatment emergent beam images to the reference image, and the tolerance is determined according to a fluctuation range of the plurality of pixel ratios. The same phantom can also be used for multiple simulation treatments, and the pixel ratio of a plurality of treatment emergent beam images and the reference image can be obtained to determine the tolerance. In some embodiments, the tolerance is a total tolerance that includes all possible error-generating factors. For example, tolerances under the combined influence of factors including signal to noise ratio, output factors, penumbra position, non-uniform ray effects or device stability factors. In some embodiments, the reasonable fluctuation range of some factors can be artificially changed, so that a plurality of corresponding simulation ratios are obtained, and a tolerance range is determined. For example, a simulation experiment may be performed according to a treatment plan with the accelerator in good condition, and an ideal simulation ratio may be measured and calculated. The beam dose produced by the accelerator typically fluctuates reasonably between-3% and + 3%. The manual simulation can change the accelerator dosage manually, so that the accelerator dosage generates dosage fluctuation of-3% to + 3%, the fluctuation simulation ratio is measured and calculated through simulation experiments, and if the fluctuation simulation ratio has 5% fluctuation above or below the ideal simulation ratio, the tolerance can be determined to be 6%.

In some embodiments, the factors may be simulated separately, the tolerance corresponding to each factor is determined, and then the tolerances of all the factors are calculated to determine the total tolerance.

In some embodiments, a relationship between beam dose and signal-to-noise ratio may be established, for example, a machine learning model or a functional relationship. And measuring the signal-to-noise ratio on the detector, and establishing the relation between the dose and the signal-to-noise ratio by using the ratio of the signal measured on the detector to the noise under the condition that the analog dose is different. And determining a theoretical signal-to-noise ratio according to planned dose data, obtaining a ratio fluctuation range generated by the signal-to-noise ratio, and determining the tolerance corresponding to the signal-to-noise ratio factor.

In some embodiments, the output factor is the ratio of the absorbed dose of any irradiation field to the absorbed dose of the reference irradiation field at a given point under the same measurement conditions. The relationship between the absorbed dose and the field size at a certain point on the central axis of the ray bundle in the irradiation object is shown. The size of the field of the treatment plan and the size of the imaging field are different, and output factors are different, so that the dosage is in error, and the fluctuation of the ratio is generated. In a simulation experiment, under the condition of ensuring that the shape of the field and the central axis of the incident beam are not changed, the size of the field is changed within a certain range to obtain a plurality of simulation ratios, and the relationship between the variation of the field size and the ratio fluctuation value is determined. And determining the tolerance corresponding to the difference of the output factors according to the difference between the planning field and the imaging field.

In some embodiments, the penumbra position is a proportion of the penumbra-affected area in the portal boundary area. In some embodiments, the ratio of the penumbra position in the boundary area can be changed, the pixel ratios between the plurality of treatment emergent beam images and the reference image are obtained through simulation, the fluctuation range of the pixel ratios is determined, and the corresponding tolerance of the penumbra position is determined. For example, a simulation experiment may be performed with the boundary region 50% at the penumbra position, the simulation resulting in a pixel ratio between the treatment exit beam image and the reference fiducial image. And then increasing or decreasing the proportion of the penumbra position, carrying out a plurality of simulation experiments to obtain a plurality of pixel ratios, determining the relation between the proportion of the penumbra position and the fluctuation range of the pixel ratio, and obtaining the corresponding tolerance of the penumbra position according to the proportion data of the penumbra position in the boundary area in the plan.

In some embodiments, the radiation within the field is generally non-uniform, the dose rate for the radiation at the center may be higher, the dose rate for the radiation near the edges of the field may be lower, and a peak may appear in the middle of the radiation. Movement of the isocenter position can cause the beam peak to move, creating a dose error. In some embodiments, a plurality of simulation ratios corresponding to isocenters with different position coordinates may be simulated, optionally selecting two isocenter simulation data to determine a ratio fluctuation value generated by two isocenters, establishing a relationship between the isocenter displacement and the ratio fluctuation value, and determining the ratio fluctuation value generated by each unit of isocenter displacement. And determining the tolerance corresponding to the ray non-uniformity factor generated by the movement of the isocenter according to the imaging isocenter correction quantity. In some embodiments, the effect of ray non-uniformity on pixel value ratio fluctuations may also be directly reduced. For example, in order to reduce the influence of the ray non-uniformity, the imaging emergent beam image and the treatment emergent beam image formed by the uniform ray can be obtained by using an idle-scan image formed by the maximum field through the air on the two-dimensional detector as a denominator to respectively remove the imaging emergent beam image and the treatment emergent beam image formed by the uniform ray, the imaging emergent beam image formed by the uniform ray is corrected in position coordinates and then is established as a reference image, and the treatment emergent beam image formed by the uniform ray is compared with the reference image to calculate a pixel value so as to eliminate the influence of the non-uniform ray.

At step 820, an allowable range may be determined based on the simulated ratio. In some embodiments, step 820 may be performed by decision module 320. In some embodiments, a fluctuation range of the plurality of simulated ratios may be determined, and the fluctuation range of the simulated ratios may be determined as the tolerance. The tolerance may be a total tolerance that includes all possible factors that may cause errors. For example, tolerances under the combined influence of factors including signal to noise ratio, output factors, penumbra position, non-uniform ray effects or device stability factors. In some embodiments, a fluctuation range for a plurality of simulated ratios may be determined, with some relaxation based on the fluctuation range in determining the tolerance. For example, the simulated ratio fluctuates within 5% of the center value, the range can be relaxed to 6%, and 6% is set as the tolerance. In some embodiments, a fluctuation range for a plurality of simulated ratios may be determined, and the tolerance determined by further narrowing the range based on the fluctuation range. For example, if a plurality of simulated ratios obtained under the condition that the range of the treatment plan is exceeded are simulated in the simulation experiment, and the fluctuation range of the simulated ratios is determined to be 7%, the range can be further narrowed on the basis of the fluctuation range of the simulated ratios when the tolerance is determined, and 5% can be determined as the tolerance.

In some embodiments, the final total tolerance may also be obtained by calculating single-factor tolerances obtained by individually simulating each influencing factor. In some embodiments, the tolerances determined by multiple separate factor simulation experiments may be weighted to determine the final tolerance. For example, the weight of the tolerance corresponding to the penumbra position may be set to 2, the weight of the tolerance corresponding to the output factor may be set to 1.5, and the final tolerance may be obtained by multiplying the two tolerances by the weights, respectively, and then adding the two tolerances. In some embodiments, the tolerance with the largest value among the tolerances corresponding to the multiple factors may be used as the total tolerance. For example, if the tolerance corresponding to the output factor is 1.5%, the tolerance corresponding to the penumbra position is 10%, and the tolerance corresponding to the influence of the uneven ray is 1%, the tolerance corresponding to the penumbra position can be used as the total tolerance.

Fig. 9 is an exemplary flow chart of a radiation therapy exit beam monitoring method according to some embodiments of the present application. Flow 900 may be performed by processing logic that may comprise hardware (e.g., circuitry, dedicated logic, programmable logic, microcode, etc.), software (instructions run on a processing device to perform hardware simulation), etc., or any combination thereof.

The imaging beam and the treatment beam are radiation of the same energy level in this application, except that the dose rate of the imaging beam and the dose rate of the treatment beam are different. Therefore, in an ideal case, the pixel values of the imaged emergent beam image and the pixel values of the treated emergent beam image of the same region should be in a multiple relation, and the ratio of the two should be constant. And establishing a reference image according to the imaging emergent beam image, calculating the pixel ratio of the treatment emergent beam image and the reference image, and monitoring the dose distribution of the treatment emergent beam through the pixel ratio.

Step 910, acquiring a reference image. Step 910 may be performed by acquisition module 310. In some embodiments, the reference image may be determined based on the imaged emergent beam image. In some embodiments, the initial reference image may be obtained by position coordinate correction from the imaged emergent beam image. In some embodiments, the initial reference image may be position-matched by a treatment field, a region corresponding to the treatment field in the initial reference image is obtained, and the region is determined as the reference image. In some embodiments, the acquisition module may acquire the reference baseline image via network 120, processing device 140, terminal 130, and/or storage device 150.

Step 920 may acquire a real-time treatment exit beam image. In some embodiments, step 920 may be performed by module 310. In some embodiments, the real-time treatment exit beam image may be generated based on exit beams obtained by the treatment input beam through the irradiation subject during the current radiation treatment procedure. In some embodiments, the treatment input beam may be generated by a linear accelerator. In some embodiments, the treatment input beam may be an X-ray beam. In some embodiments, the treatment input beam may pass through one or more collimators of a particular shape to form a beam having a cross-sectional shape sized to fit the treatment area, such as a beam having a cross-sectional shape that is smaller than or equal to the tumor area of the patient. In some embodiments, the treatment device may include an imaging assembly that may receive an exit beam of the treatment input beam through the irradiation target, forming a treatment exit beam projection image. In some embodiments, the imaging assembly may acquire the treatment exit beam projection images at a frequency. For example, treatment emergent beam images are acquired every 0.5 seconds. In some embodiments, the therapeutic incident beam may be a megavolt (>1MeV) energy level cone beam. In some embodiments, the source of radiation may be rotated about the isocenter with the gantry in a fixed plane so that the therapeutic input beam may be angled to irradiate the target. For example, the gantry rotates left to 260 ° and right to 100 ° in the XOY plane around O, the treatment input beam may illuminate the target at some set angle between 260 ° (left) and-100 ° (right), producing a treatment output beam image corresponding to the set angle.

In some embodiments, a correction of the treatment isocenter may be made before each treatment to bring the treatment isocenter into agreement with the treatment plan isocenter. In some embodiments, image-guided treatment-guided image registration may be performed prior to each treatment to determine a three-dimensional correction between the imaging isocenter and the planning isocenter. The treatment isocenter is corrected based on a three-dimensional correction between the imaging isocenter and the planning isocenter. For example, by matching the treatment guidance image with the positioning CT image of the treatment plan, the amounts of correction in X, Y and the Z direction of the imaging isocenter and the plan isocenter are +2mm, -1.5mm, and +3mm, respectively, and the three-dimensional spatial position of the table 160 is adjusted based on the correction amounts, and the table 160 is moved 3mm in the Z-axis negative direction, shifted 2mm in the X-axis negative direction, and shifted 1.5mm in the Y-axis positive direction, so that the current isocenter position coincides with the isocenter position in the treatment plan. In some embodiments, during actual treatment, the treatment beam is required to irradiate the tumor from different angles, so that the accelerator 111 rotates with the gantry 113, so that projection images of the treatment exit beam at different angles can be obtained. Before radiotherapy, imaging is carried out at a plurality of treatment angles, and a reference datum image corresponding to the treatment angle is established according to an imaging projection image at each angle. During treatment, a treatment emergent beam image at a corresponding treatment angle needs to be acquired, pixel ratio calculation is carried out on the treatment emergent beam image and a reference image at a corresponding angle, and emergent beam dosage at the angle is monitored. For example, the beam is irradiated at a plurality of angles between 260 degrees (left) and 100 degrees (right) during treatment, before treatment, an imaged emergent beam image at each angle needs to be acquired, a reference image at each angle is established, a treated emergent beam image at each angle is acquired, the treated emergent beam image at each angle is compared with the reference image at the corresponding angle, and emergent beam dose is monitored.

In some embodiments, collimator angle correction may be performed on the treatment exit beam image. As mentioned above, the angle of the imaging collimator is 0 °, and the collimator is usually rotated by a certain angle during treatment. In order to match the treatment collimator rotation angle with the plan collimator angle, the mask image may be rotated when the reference image is established, and the rotated mask image and the initial reference image are subjected to pixel and operation to obtain a reference image with a rotated boundary, so that the reference image is matched with the treatment plan.

In some embodiments, the treatment exit beam may be processed to eliminate the effect of non-uniform radiation on tolerance. In some embodiments, the radiation within the field is generally non-uniform, the dose rate for the radiation at the center may be higher, the dose rate for the radiation near the edges of the field may be lower, and a peak may appear in the middle of the radiation. When the position of the radiotherapy equipment moves, the peak value also moves, and the deviation of the imaging isocenter or the treatment isocenter can cause the peak value of the dose to move, so that dose errors are generated. In some embodiments, the effects of ray non-uniformity may be eliminated by dividing the imaged exit beam image and the treatment exit beam image by the null scan signal at the corresponding coordinates, respectively. In some embodiments, the null scan signal may be obtained by first acquiring the beam receive signal when the target is not illuminated, but only air. The null scan signal is the attenuation of the beam in air. In some embodiments, the reference image may be created by using an imaged emergent beam image formed by the imaged emergent beam image and the uniform ray obtained by the dividing operation of the null scan signal as an imaged emergent beam image for creating a reference. In some embodiments, a treatment emergent beam image formed by the uniform rays obtained by dividing the treatment emergent beam by the null scan signal can be used as a final treatment emergent beam image, and the pixel ratio can be calculated with the reference image so as to reduce the influence of the non-uniformity contrast value and the tolerance of the rays.

At step 930, it may be determined whether the difference in pixel values between the real-time treatment emergence beam image and the reference image satisfies a preset condition based on the real-time treatment emergence beam image and the reference image. In some embodiments, step 930 may be performed by decision module 320. In some embodiments, the imaging beam and the treatment beam are radiation of the same energy level except that a dose rate of the imaging beam and a dose rate of the treatment beam are different. Therefore, in an ideal case, the pixel ratio of the imaged emergent beam image and the treated emergent beam image of the same region should be a multiple relation, and the ratio should be constant. And ideally the ratio should be the ratio of the imaging dose rate to the treatment plan dose rate. In practice, however, the ratio is hardly constant but fluctuates within a certain range due to factors such as equipment problems and system errors. In some embodiments, a reasonable preset condition may be set, and the treatment exit beam meets the requirements of the treatment plan as long as the ratio of the pixel values of the real-time treatment exit beam image and the reference image is within the reasonable preset condition. In some embodiments, a pixel value ratio of corresponding pixel points of the real-time treatment emergent beam image and the reference image may be determined, and whether the pixel value difference is within the tolerance range may be determined based on the pixel value ratio. In some embodiments, the tolerance may be determined based on one or a combination of signal-to-noise ratio, output factors, penumbra position, non-uniform ray effects, or device stability factors. The determination of tolerance may be found elsewhere herein, such as in relation to FIG. 8.

Based on the determination, the radiation therapy treatment process can be controlled, step 940. In some embodiments, step 940 may be performed by execution module 330. In some embodiments, when the difference in pixel values of the real-time treatment exit beam image and the reference image is outside the tolerance range, the current treatment is stopped. In some embodiments, a combination of one or more of aging of the apparatus, failure of the apparatus, errors in the radiation therapy system, weight changes in the patient, tissue changes, organ changes in the patient's breathing or other body movements during treatment, or body shifts in the patient over time may cause the treatment emergent beam dose error to be large and out of tolerance. If the ratio of the pixel values of the real-time treatment emergent beam image and the reference image exceeds the tolerance range, the treatment emergent beam does not meet the requirement of plan, the dose distribution of the treatment emergent beam can be seriously deviated from the plan position, and the tissue or organ in a non-tumor area can be damaged. Or the dose rate of the radiation does not meet the plan requirements, and the treatment effect is influenced. In some embodiments, after stopping the current treatment, the staff may find the cause of the error, and if the cause is the equipment failure, the positioning error and the system error, the staff is required to correct the problem and then to recover the treatment. If the change is due to a change in patient weight or a change in tissue or organ, the CT may be rescanned as necessary, the treatment plan re-planned and the reference baseline image updated, and the treatment resumed.

Fig. 10A to 10C are comparison results of the verification experiment for the aforementioned outgoing beam monitoring method. Three clinical typical problems of body weight change, internal tissue change, rotation and positioning errors and the like of a die body are simulated respectively through experiments, and the feasibility and the sensitivity of dose monitoring of the treatment emergent beam applied to the radiotherapy process are preliminarily analyzed.

Fig. 10A shows the monitoring of the radiation therapy exit beam as the phantom body weight was simulated. The leftmost column of images is the reference base image with the angle of the source on the gantry at 45 °, 0 °, 315 ° and 270 °. Wherein the reference image may be generated from an imaged exit beam image obtained by illuminating the reference phantom with the imaged incident beam. The middle column image is a ratio distribution map of the treatment exit beam image at 45 °, 0 °, 315 ° and 270 ° gantry angles, respectively, of the phantom as a weight change to the corresponding reference fiducial image. In the experiment, the phantom after the body weight change can be obtained by covering or removing a covering on the reference phantom. The rightmost column is a histogram of the reference ratio and the simulated ratio. The dotted line represents the histogram statistical result of the ratio distribution diagram of the treatment emergent beam image of the reference phantom and the reference image, and the solid line represents the histogram statistical result of the ratio distribution diagram of the treatment emergent beam image of the phantom after the weight change and the reference image. It can be seen that weight changes can cause large fluctuations in the ratio of pixels of the treatment emergent beam image to the reference baseline image. Therefore, the radiation therapy monitoring method can monitor the influence of the weight change of the radiation target on the treatment emergent beam dose.

FIG. 10B shows the monitoring of the radiation therapy exit beam as the tissue inside the phantom is changed. The leftmost column of images is the reference base image with the angle of the source on the gantry at 45 °, 0 °, 315 ° and 270 °. Wherein the reference image may be generated from an imaged exit beam image obtained by illuminating the reference phantom with the imaged incident beam. The middle column image is a ratio distribution diagram of the treatment emergent beam image and the corresponding reference datum image under the frame angles of 45 degrees, 0 degrees, 315 degrees and 270 degrees respectively for the phantom with the internal tissue change. In the experiment, the medium in the reference model can be changed from air to contrast medium, so that the change of the content in the intestinal tract can be simulated. The rightmost column is a histogram of the reference ratio and the simulated ratio. The dotted line represents the histogram statistical result of the ratio distribution diagram of the treatment emergent beam image of the reference phantom and the reference image, and the solid line represents the histogram statistical result of the ratio distribution diagram of the treatment emergent beam image of the phantom after tissue change and the reference image. It can be seen that tissue changes can cause large fluctuations in the ratio of pixels of the treatment emergent beam image to the reference image. Therefore, the radiotherapy monitoring method can monitor the influence of the change of the radiation target tissue on the treatment emergent beam dose.

FIG. 10C shows the monitoring of the radiation therapy exit beam with different degrees of error in the positioning of the phantom. The leftmost column of images is the reference base image with the angle of the source on the gantry at 45 °, 0 °, 315 ° and 270 °. Wherein the reference image may be generated from an imaged exit beam image obtained by illuminating the reference phantom with the imaged incident beam. The images in the middle column are distribution diagrams of the ratio of the treatment emergent beam image to the corresponding reference standard image under the frame angles of 45 degrees, 0 degrees, 315 degrees and 270 degrees respectively for the motif with the changed positioning. In the experiment, the position of the reference phantom can be deviated, or the reference phantom can be rotated to simulate the displacement change. The rightmost column is a histogram of the reference ratio and the simulated ratio. The dotted line represents the histogram statistical result of the ratio distribution diagram of the treatment emergent beam image of the reference phantom and the reference image, and the solid line represents the histogram statistical result of the ratio distribution diagram of the treatment emergent beam image of the phantom after the positioning change and the reference image. It can be seen that the repositioning variation causes large fluctuations in the ratio of pixels of the treatment emergent beam image to the reference image. Therefore, the radiation therapy monitoring method can monitor the influence of the swing position change of the radiation target on the dose of the outgoing beam of the therapy.

Therefore, if similar influence factors occur to a human body or a system error becomes large in the treatment process, the monitoring method can find the change of the emergent beam dose error and monitor the emergent beam dose distribution so as to avoid the injury to a non-tumor area or the influence of inaccurate dose on the normal treatment process in the radiotherapy process.

One of the embodiments of the present application further provides a method for acquiring a reference baseline image for radiation therapy. In some embodiments, the method comprises: acquiring an emergent beam obtained by the imaging incident beam penetrating through a radiation object, and generating an imaging emergent beam image based on the emergent beam; correcting the position coordinates of the imaging emergent beam image to obtain an initial reference image; performing position matching on the initial reference image based on the treatment field to obtain a region corresponding to the treatment field in the initial reference image, and determining the region as the reference image; wherein the imaging input beam and the therapeutic input beam of the radiotherapy are same-energy-level beams. In some embodiments, the imaging input beam and the therapy input beam are from the same radiation source. For example, the imaging input beam and the therapy input beam are generated by the same accelerator. In some embodiments, the imaging input beam and the therapy input beam may be spectrally identical beams. For example, the imaging input Beam and the treatment input Beam may originate from different radiation sources, and the imaging radiation source and the treatment radiation source may be first Beam matched (Beam match) to adjust the imaging input Beam and the treatment input Beam to be beams of the same energy spectrum.

One of the embodiments of the present application further provides a system for acquiring a reference fiducial image for radiation therapy. In some embodiments, the system comprises: the acquisition module is used for acquiring an emergent beam obtained by the imaging incident beam penetrating through the radiation object and generating an imaging emergent beam image based on the emergent beam; the reference image determining module is used for correcting the position coordinates of the imaging emergent beam image to obtain an initial reference image; performing position matching on the initial reference image based on the treatment field to obtain a region corresponding to the treatment field in the initial reference image, and determining the region as the reference image; wherein the imaging input beam and the therapeutic input beam of the radiotherapy are same-energy-level beams.

The beneficial effects that may be brought by the embodiments of the present application include, but are not limited to: (1) the treatment beam and the imaging beam are beams with the same energy level, and a reference image can be established through the imaging emergent beam image, so that the monitoring of the dose of the treatment emergent beam is facilitated; (2) methods of establishing a reference fiducial image based on an imaged emergent beam image and a treatment plan and determining tolerances are provided, improving monitoring accuracy; (3) since the treatment beam and the imaging beam are the same energy level beam, the imaging dose can be recorded and counted into the treatment dose, and the risk burden of the patient is prevented from being increased additionally. It is to be noted that different embodiments may produce different advantages, and in different embodiments, any one or combination of the above advantages may be produced, or any other advantages may be obtained.

Having thus described the basic concept, it will be apparent to those skilled in the art that the foregoing detailed disclosure is to be considered merely illustrative and not restrictive of the broad application. Various modifications, improvements and adaptations to the present application may occur to those skilled in the art, although not explicitly described herein. Such modifications, improvements and adaptations are proposed in the present application and thus fall within the spirit and scope of the exemplary embodiments of the present application.

Also, this application uses specific language to describe embodiments of the application. Reference throughout this specification to "one embodiment," "an embodiment," and/or "some embodiments" means that a particular feature, structure, or characteristic described in connection with at least one embodiment of the present application is included in at least one embodiment of the present application. Therefore, it is emphasized and should be appreciated that two or more references to "an embodiment" or "one embodiment" or "an alternative embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, some features, structures, or characteristics of one or more embodiments of the present application may be combined as appropriate.

Moreover, those skilled in the art will appreciate that aspects of the present application may be illustrated and described in terms of several patentable species or situations, including any new and useful combination of processes, machines, manufacture, or materials, or any new and useful improvement thereon. Accordingly, various aspects of the present application may be embodied entirely in hardware, entirely in software (including firmware, resident software, micro-code, etc.) or in a combination of hardware and software. The above hardware or software may be referred to as "data block," module, "" engine, "" unit, "" component, "or" system. Furthermore, aspects of the present application may be represented as a computer product, including computer readable program code, embodied in one or more computer readable media.

The computer storage medium may comprise a propagated data signal with the computer program code embodied therewith, for example, on baseband or as part of a carrier wave. The propagated signal may take any of a variety of forms, including electromagnetic, optical, etc., or any suitable combination. A computer storage medium may be any computer-readable medium that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. Program code located on a computer storage medium may be propagated over any suitable medium, including radio, cable, fiber optic cable, RF, or the like, or any combination of the preceding.

Computer program code required for the operation of various portions of the present application may be written in any one or more programming languages, including an object oriented programming language such as Java, Scala, Smalltalk, Eiffel, JADE, Emerald, C + +, C #, VB.NET, Python, and the like, a conventional programming language such as C, Visual Basic, Fortran 2003, Perl, COBOL 2002, PHP, ABAP, a dynamic programming language such as Python, Ruby, and Groovy, or other programming languages, and the like. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer through any network format, such as a Local Area Network (LAN) or a Wide Area Network (WAN), or the connection may be made to an external computer (for example, through the Internet), or in a cloud computing environment, or as a service, such as a software as a service (SaaS).

Additionally, the order in which elements and sequences of the processes described herein are processed, the use of alphanumeric characters, or the use of other designations, is not intended to limit the order of the processes and methods described herein, unless explicitly claimed. While various presently contemplated embodiments of the invention have been discussed in the foregoing disclosure by way of example, it is to be understood that such detail is solely for that purpose and that the appended claims are not limited to the disclosed embodiments, but, on the contrary, are intended to cover all modifications and equivalent arrangements that are within the spirit and scope of the embodiments herein. For example, although the system components described above may be implemented by hardware devices, they may also be implemented by software-only solutions, such as installing the described system on an existing server or mobile device.

Similarly, it should be noted that in the preceding description of embodiments of the application, various features are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure aiding in the understanding of one or more of the embodiments. This method of disclosure, however, is not intended to require more features than are expressly recited in the claims. Indeed, the embodiments may be characterized as having less than all of the features of a single embodiment disclosed above.

Numerals describing the number of components, attributes, etc. are used in some embodiments, it being understood that such numerals used in the description of the embodiments are modified in some instances by the use of the modifier "about", "approximately" or "substantially". Unless otherwise indicated, "about", "approximately" or "substantially" indicates that the number allows a variation of ± 20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximations that may vary depending upon the desired properties of the individual embodiments. In some embodiments, the numerical parameter should take into account the specified significant digits and employ a general digit preserving approach. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the range are approximations, in the specific examples, such numerical values are set forth as precisely as possible within the scope of the application.

The entire contents of each patent, patent application publication, and other material cited in this application, such as articles, books, specifications, publications, documents, and the like, are hereby incorporated by reference into this application. Except where the application is filed in a manner inconsistent or contrary to the present disclosure, and except where the claim is filed in its broadest scope (whether present or later appended to the application) as well. It is noted that the descriptions, definitions and/or use of terms in this application shall control if they are inconsistent or contrary to the statements and/or uses of the present application in the material attached to this application.

Finally, it should be understood that the embodiments described herein are merely illustrative of the principles of the embodiments of the present application. Other variations are also possible within the scope of the present application. Thus, by way of example, and not limitation, alternative configurations of the embodiments of the present application can be viewed as being consistent with the teachings of the present application. Accordingly, the embodiments of the present application are not limited to only those embodiments explicitly described and depicted herein.

Claims

1. A radiation treatment exit beam monitoring system, comprising:

the acquisition module is used for acquiring a reference image; the reference image is determined based on an imaged emergent beam image generated based on an emergent beam obtained by an imaged incident beam through a radiation object;

the acquisition module is also used for acquiring a real-time treatment emergent beam image; the real-time treatment emergent beam image is generated based on an emergent beam obtained by a treatment incident beam penetrating through a radiation object in the current radiotherapy process;

the judging module is used for determining the pixel value ratio of the pixel points corresponding to the real-time treatment emergent beam image and the reference standard image based on the real-time treatment emergent beam image and the reference standard image; judging whether the pixel value difference is within a tolerance range or not based on the pixel value ratio;

the execution module is used for controlling the radiation treatment process based on the judgment result;

wherein the imaging input beam and the therapeutic input beam of the radiotherapy are same-energy-level beams.

2. The system of claim 1, wherein the imaging input beam and the therapy input beam are from a same radiation source.

3. The system of claim 1, wherein the imaged exit beam image is acquired prior to radiation therapy.

4. The system of claim 3, wherein the imaged exit beam image is an image used to image guide user positioning prior to radiation treatment.

5. The system of claim 1, further comprising a reference baseline image determination module to:

correcting the position coordinates of the imaging emergent beam image to obtain an initial reference image;

and performing position matching on the initial reference image based on the treatment field to obtain a region corresponding to the treatment field in the initial reference image, and determining the region as the reference image.

6. The system of claim 5, wherein the reference baseline image determination module is further to:

acquiring an imaging isocenter position and an isocenter position of a treatment plan;

position coordinate correction is performed on the imaged emergent beam image based on a difference between the imaged isocenter position and the treatment plan isocenter position.

7. The system of claim 5, wherein the reference baseline image determination module is further to:

acquiring the angle of a collimator during imaging and the collimator angle of a treatment plan;

determining an angular difference between a collimator angle at imaging and a collimator angle of the treatment plan;

and correcting the position coordinates of the imaging emergent beam image based on the angle difference.

8. The system of claim 5, wherein the reference baseline image determination module is further to:

determining a treatment field based on position data of the grating in the treatment plan to generate a mask image;

and operating the mask image and the initial reference image to obtain the corresponding region.

9. The system of claim 8, wherein the reference baseline image determination module is further to:

acquiring at least one treatment emergent beam image;

determining boundary information of an actual treatment field based on the treatment emergent beam image;

verifying the mask image based on the boundary information.

10. The system of claim 1, further comprising a reference baseline image determination module to:

determining a digital reconstructed image of the planned CT image; the planned CT image is a CT scanning image used for determining a treatment plan before treatment;

obtaining an initial reference image based on the digital reconstructed image of the planned CT image and the imaged emergent beam image;

11. The system of claim 10, wherein the reference baseline image determination module is further to:

according to S₀Exp (- μ Ι _ calculating a plurality of projection data; and determining a digitally reconstructed image of the planned CT image based on the plurality of projection data;

wherein S is₀Subtracting a background value from the null scan signal, wherein the null scan signal is a signal collected by a detector when rays are attenuated only in the air, and the background value is an environmental signal collected by the detector when a radioactive source does not work;

mu is the average attenuation coefficient of the ray passing through the human body from one direction;

l is the length of the part of the body located in the linear distance between the detector and the planned CT radiation source.

12. The system of claim 10, wherein the reference baseline image determination module is further to:

and carrying out deformation registration on the digital reconstruction image of the planned CT and the imaging emergent beam image based on an image registration algorithm to obtain the initial reference image.

13. The system of claim 1, wherein the tolerance range is determined based on a combination of one or more of:

signal to noise ratio, output factor, penumbra position, non-uniform ray effects or device stability factors.

14. The system of claim 1, wherein the execution module is further to:

when the pixel value difference exceeds the tolerance range, the current treatment is stopped.

15. A radiation treatment exit beam monitoring apparatus, comprising at least one processor and at least one memory;

the at least one memory is for storing computer instructions;

the at least one processor is configured to execute at least some of the computer instructions to perform the functions defined by the radiation therapy exit beam monitoring system of any one of claims 1-14.

16. A computer readable storage medium storing computer instructions which, when read by a computer, cause the computer to perform the functions defined by the radiation therapy exit beam monitoring system of any one of claims 1 to 14.

17. A method of acquiring a reference fiducial image for radiation therapy, comprising:

acquiring an emergent beam obtained by the imaging incident beam penetrating through a radiation object, and generating an imaging emergent beam image based on the emergent beam;

performing position matching on the initial reference image based on the treatment field to obtain a region corresponding to the treatment field in the initial reference image, and determining the region as the reference image;

18. A reference fiducial image acquisition system for radiation therapy, comprising:

the acquisition module is used for acquiring an emergent beam obtained by the imaging incident beam penetrating through the radiation object and generating an imaging emergent beam image based on the emergent beam;

the reference image determining module is used for correcting the position coordinates of the imaging emergent beam image to obtain an initial reference image; performing position matching on the initial reference image based on the treatment field to obtain a region corresponding to the treatment field in the initial reference image, and determining the region as the reference image;

19. An apparatus for acquiring reference images for radiotherapy, the apparatus comprising at least a processor and at least a memory;

the at least one memory is for storing computer instructions;

the at least one processor is configured to execute at least some of the computer instructions to implement the method of acquiring a reference fiducial image for radiation treatment of claim 17.

20. A computer readable storage medium storing computer instructions which, when read by a computer, cause the computer to perform the method of acquiring a reference fiducial image for radiation therapy as set forth in claim 17.

21. A method of acquiring a reference fiducial image for radiation therapy, comprising:

obtaining an initial reference image based on the digital reconstruction image and the imaging emergent beam image of the planned CT image;

wherein the imaging input beam and the therapeutic input beam of the radiotherapy are the same energy level beams.

22. An apparatus for acquiring a reference image for radiotherapy, comprising:

the image reconstruction module is used for determining a digital reconstruction image of the planned CT image; the planned CT image is a CT scanning image used for determining a treatment plan before treatment;

the registration module is used for obtaining an initial reference standard image based on the digital reconstruction image and the imaging emergent beam image of the planned CT image;

the reference benchmark image determining module is used for carrying out position matching on the initial reference benchmark image based on the treatment field, obtaining a region corresponding to the treatment field in the initial reference benchmark image and determining the region as the reference benchmark image;

23. An apparatus for acquiring reference images for radiotherapy, the apparatus comprising at least a processor and at least a memory;

the at least one memory is for storing computer instructions;

the at least one processor is configured to execute at least some of the computer instructions to implement the method of acquiring a reference fiducial image for radiation therapy as set forth in claim 21.

24. A computer readable storage medium storing computer instructions which, when read by a computer, cause the computer to perform the method of acquiring a reference fiducial image for radiation therapy as set forth in claim 21.