Radiotherapy system and method

Abstract

A radiation therapy system (100) includes a magnetic resonance imaging (MRI) device (310) and a radiation therapy device (320). The MRI apparatus (310) may be configured to acquire magnetic resonance imaging data regarding a region of interest (ROI). The radiotherapy device (320) may be configured to apply therapeutic radiation to at least a portion of the ROI when rotated with the gantry (321 '). The radiotherapy device (320) may include an eddy current reduction device (700) coupled to the gantry. The eddy current reduction device (700) may include at least one structure (721, 722, 723, 724), where each of the at least one structure (721, 722, 723, 724) may include at least two internal structures, and at least some of the at least two internal structures are electrically disconnected from each other.

Description

Description of the case

[0001] This application is a divisional application filed for the Chinese application with the application date of August 26, 2019, application number 201980099634.8, and invention name “Radiotherapy System and Method”. Technical Field

[0002] The present invention generally relates to radiation therapy systems, and more particularly to an image-guided radiation therapy system that combines radiation therapy technology with magnetic resonance imaging technology. Background Art

[0003] Tumor radiation therapy is currently affected by the difficulty of tracking tumor changes (e.g., movement) during different treatment phases. Today, various imaging techniques can be used to provide real-time images of tumors before or during treatment. For example, a magnetic resonance imaging (MRI) device can be used in combination with a radiotherapy device to provide an MRI image of a tumor. The combination of an MRI device and a radiotherapy device forming a treatment device can introduce interference during the operation of the treatment device, such as magnetic interference generated by the MRI device, eddy current interference generated by the radiotherapy device, etc. Therefore, it is desirable to provide a treatment device that reduces interference and provides high treatment quality. Summary of the invention

[0004] One aspect of the specification relates to a system for radiation therapy. The system may include a magnetic resonance imaging (MRI) device and a radiation therapy device. The MRI device may be configured to acquire magnetic resonance imaging data about a region of interest (ROI). The radiation therapy device may be configured to apply therapeutic radiation to at least a portion of the ROI while rotating with a gantry. The radiation therapy device may include an eddy current reduction device coupled to the gantry. The eddy current reduction device may include at least one structure, wherein each of the at least one structure may include at least two internal structures, and at least some of the at least two internal structures are electrically disconnected from each other.

[0005] In some embodiments, the vortex reducer may be part of the frame.

[0006] In some embodiments, each of the at least one structure may correspond to a block that occupies at least a portion of a rack.

[0007] In some embodiments, for at least one of the at least one structure, at least one of the size of the structure, the shape of the structure, the thickness of the structure and / or the configuration of the structure may be associated with a shielding parameter of the radiotherapy device, which is related to the magnetic field of the MRI device.

[0008] In some embodiments, for each of the at least one structure, the at least two internal structures may include at least two panels.

[0009] In some embodiments, for at least one of the at least one structures, the thickness of at least two plates may be uniform.

[0010] In some embodiments, for at least one of the at least one structure, a gap exists between at least one pair of adjacent internal structures of the at least two internal structures.

[0011] In some embodiments, for at least one of the at least one structures, the gap may be empty.

[0012] In some embodiments, for at least one of the at least one structure, an electrically insulating material may be present between at least one pair of adjacent internal structures of the at least two internal structures.

[0013] In some embodiments, for at least one of the at least one structure, at least two internal structures may be arranged in a direction to break a current loop of a simulated eddy current corresponding to the structure generated in response to a magnetic field of the MRI device.

[0014] In some embodiments, for at least one of the at least one structures, a structural parameter of the structure can be associated with a simulated eddy current intensity corresponding to the structure in response to the magnetic field of the MRI device. The structural parameter can include at least one of the number of at least two internal structures in the structure and / or the thickness of at least two internal structures included in the structure.

[0015] In some embodiments, for at least one of the at least one structures, the simulated eddy current intensity may be related to at least one of a magnetic field parameter of the MRI device, a material parameter of the structure, a distance between the MRI device and the structure, and / or a rotation speed of the gantry.

[0016] In some embodiments, the magnetic field parameters of the MRI device may include at least one of magnetic field strength and / or magnetic field direction.

[0017] In some embodiments, the material parameters of the structure may include at least one of magnetic permeability and / or electrical conductivity.

[0018] In some embodiments, at least one structure can be dynamically adjusted based on the rotational speed of the gantry.

[0019] In some embodiments, at least one structure may include at least one of a manganese-zinc-ferrite material and / or a powder metallurgy material.

[0020] In some embodiments, a radiation therapy device may include an accelerator configured to generate therapeutic radiation.

[0021] Another aspect of the specification relates to a system for radiation therapy. The system may include a magnetic resonance imaging (MRI) device and a radiation therapy device. The MRI device may be configured to acquire magnetic resonance imaging data about a region of interest (ROI). The radiation therapy device may be configured to apply therapeutic radiation to at least a portion of the ROI while the gantry is rotating. The radiation therapy device may include an eddy current reduction device coupled to the gantry. The eddy current reduction device may include at least one block, wherein the at least one block may include at least two conductors, and at least some of the at least two conductors are electrically disconnected from each other.

[0022] Another aspect of the specification relates to a system for radiation therapy. The system may include a magnetic resonance imaging (MRI) device and a radiation therapy device. The MRI device may be configured to acquire magnetic resonance imaging data about a region of interest (ROI). The radiation therapy device may be configured to apply therapeutic radiation to at least a portion of the ROI as the gantry rotates. The radiation therapy device may include an eddy current reduction device coupled to the gantry. The eddy current reduction device may include at least one structure, wherein each of the at least one structure may occupy at least a portion of the gantry.

[0023] Some additional features of this specification may be explained in the following description. Some additional features of this specification will be apparent to those skilled in the art through study of the following description and corresponding drawings or understanding of the production or operation of the embodiments. Features of this specification may be realized and implemented by practicing or using various aspects of the methods, tools, and combinations described in the detailed examples discussed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] This specification will be further described by exemplary embodiments. These exemplary embodiments will be described in detail by the accompanying drawings. These embodiments are non-limiting exemplary embodiments, in which the same numbers in each figure represent similar structures, wherein:

[0025] Figure 1 is a schematic diagram of an exemplary radiation therapy system according to some embodiments of the present specification;

[0026] Figure 2 is an exemplary flow chart of applying therapeutic radiation in a radiation therapy system according to some embodiments of the present specification;

[0027] Figure 3-A is a schematic diagram of an exemplary treatment device according to some embodiments of the present specification;

[0028] Figure 3-B is a schematic diagram of another exemplary treatment device according to some embodiments of the present specification;

[0029] Figure 4 is a schematic diagram of an upper portion of a cross-section of an exemplary treatment device viewed along the X direction according to some embodiments of the present specification;

[0030] Figure 5-A is a schematic diagram of a perspective view of an exemplary therapeutic device according to some embodiments of the present specification;

[0031] Figure 5-B is a schematic diagram of a perspective view of another exemplary therapeutic device according to some embodiments of the present specification;

[0032] Figure 6 is a schematic diagram of exemplary eddy currents on a shielding structure according to some embodiments of the present specification;

[0033] Figure 7 is a schematic diagram of an exemplary vortex reduction device according to some embodiments of the present specification;

[0034] Figure 8 is a schematic diagram of an exemplary arrangement of at least two internal structures included in the structure of the vortex reducing device according to some embodiments of the present specification;

[0035] Figure 9-A to Figure 9-D is a schematic diagram of an exemplary internal structure included in the structure of the vortex reducing device according to some embodiments of the present specification;

[0036] Figure 10-A is a schematic diagram of exemplary eddy current intensities associated with a radiotherapy apparatus without an eddy current reducing apparatus according to some embodiments of the present specification; and

[0037] Figure 10-B is a schematic diagram of exemplary eddy current intensities associated with a radiotherapy apparatus having an eddy current reducing apparatus according to some embodiments of the present specification. DETAILED DESCRIPTION

[0038] In order to more clearly illustrate the technical solutions of the embodiments of this specification, the drawings required for use in the description of the embodiments will be briefly introduced below. However, it should be understood by those skilled in the art that this specification can be implemented without these details. In other cases, in order to avoid unnecessarily obscuring various aspects of this specification, well-known methods, processes, systems, components and / or circuits have been described at a higher level. For those of ordinary skill in the art, it is obvious that various changes can be made to the disclosed embodiments, and the general principles defined in this specification can be applied to other embodiments and application scenarios without departing from the principles and scope of this specification. Therefore, this specification is not limited to the embodiments shown, but conforms to the broadest scope consistent with the scope of the patent application.

[0039] The terms used in this specification are for the purpose of describing specific example embodiments only and are not restrictive. The singular forms "a", "an" and "the" as used in this specification may also include plural forms unless the context clearly indicates an exception. It should also be understood that the terms "including" and "comprising" as used in this specification only indicate the presence of the features, integers, steps, operations, components and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, components, parts and / or combinations thereof.

[0040] These and other features, characteristics and functions and methods of operation of the related structural elements, as well as the combination of parts and manufacturing economy of the present specification may become more apparent from the following description of the accompanying drawings, which form a part of the present specification. However, it should be understood that the drawings are for illustration and description purposes only and are not intended to limit the scope of the present specification. It should be understood that the drawings are not drawn to scale.

[0041] One aspect of the specification relates to systems and methods for radiation therapy. The system may include a magnetic resonance imaging (MRI) device configured to acquire MRI data (e.g., MR signals) about a region of interest (ROI) (e.g., a treatment region associated with a tumor). The system may also include a radiation therapy device configured to apply therapeutic radiation to at least a portion of the ROI when rotating with a gantry. During operation of the MRI device and the radiation therapy device, eddy currents may be generated on a portion of the radiation therapy device (e.g., a shielding structure) in response to a magnetic field generated by the MRI device, thereby affecting the magnetic field of the MRI device and then causing artifacts to be generated during magnetic resonance imaging. Therefore, an eddy current reduction device coupled to the gantry (or may be a part of the gantry) is introduced into the radiation therapy device, which can reduce the eddy currents generated on the radiation therapy device.

[0042] The eddy current reducing device may include at least two internal structures (e.g., at least two plates), and at least some of the at least two internal structures are electrically disconnected from each other. The at least two internal structures can cut off the conduction of eddy currents on a portion of the radiotherapy device, thereby reducing the eddy current intensity and improving the quality of treatment.

[0043] Figure 11 is a schematic diagram of an exemplary radiation therapy system according to some embodiments of the present specification. In some embodiments, the radiation therapy system 100 may be a multimodal imaging system, which includes, for example, a positron emission tomography-radiation therapy (PET-RT) system, a magnetic resonance imaging-radiation therapy (MRI-RT) system, etc. For a better understanding of the present specification, the MRI-RT system may be described as an example of the radiation therapy system 100, but it is not intended to limit the scope of the present specification.

[0044] like Figure 1 As shown, the radiation therapy system 100 may include a treatment device 110, a processing device 120, a network 130, a storage device 140, and a terminal device 150. In some embodiments, the treatment device 110, the processing device 120, the storage device 140, and / or the terminal device 150 may be interconnected and / or communicated via wireless connection, wired connection, or any combination thereof.

[0045] The treatment device 110 may include a magnetic resonance imaging (MRI) device and a radiation therapy device.

[0046] The MRI device can be configured to generate image data by scanning an area of ​​interest of the object (e.g., a treatment area associated with a tumor). In some embodiments, the object may include a body, a substance, etc., or any combination thereof. In some embodiments, the object may include a specific part of the body, such as the head, brain, neck, shoulder, arm, chest, stomach, blood vessel, knee, foot, etc., or any combination thereof. In some embodiments, the object may include a specific organ, breast, esophagus, trachea, bronchus, stomach, gallbladder, small intestine, colon, bladder, ureter, uterus, fallopian tube, etc., or any combination thereof. In this specification, the terms "object" and "subject" may be used interchangeably.

[0047] In some embodiments, the treatment device 110 may send the image data to the processing device 120, the storage device 140 and / or the terminal device 150 via the network 130 for further processing. For example, the treatment device 110 may send the image data to the processing device 120 to generate an MR image. For another example, the treatment device 110 may send the image data to the storage device 140 for storage.

[0048] The radiotherapy device can be configured to apply therapeutic radiation to at least a portion of the ROI. The radiation used here (also referred to as a "radiation beam") may include particle rays, photon rays, etc. Particle rays may include neutrons, protons, electrons, muons, heavy ions, alpha rays, etc., or any combination thereof. Photon rays may include X-rays, gamma rays, ultraviolet rays, lasers, etc., or any combination thereof. For illustrative purposes, a radiotherapy device associated with X-rays may be described as an example. In some embodiments, the treatment device 110 may generate a dose of X-rays for radiotherapy with the aid of image data provided by an MRI device. For example, the image data may be processed to locate a tumor area and / or determine the dose of the X-rays.

[0049] The processing device 120 may be configured to process data and / or information obtained from the treatment device 110, the storage device 140, and / or the terminal device 150. For example, the processing device 120 may process image data obtained from the MRI device of the treatment device 110, and reconstruct at least one MR image based on the image data. For another example, the processing device 120 may determine the treatment area and the radiation dose based on the at least one MR image. The advantages that MR images may provide include, for example, superior soft tissue contrast, high resolution, and geometric accuracy, thereby allowing accurate positioning of the treatment area. MR images may be used to detect changes in the treatment area (e.g., tumor regression or metastasis) during the determination of the treatment plan and / or the execution of the treatment, so that the original treatment plan may be adjusted accordingly. The original treatment plan may be determined before the treatment begins. For example, the original treatment plan may be determined at a predetermined time (e.g., one day, three days, one week, two weeks, one month) before the treatment begins. In the original or adjusted treatment plan, the radiation dose may be determined based on, for example, synthetic electron density information. In some embodiments, synthetic electron density information may be generated based on MR images.

[0050] In some embodiments, the processing device 120 may be a single processing device that communicates with the MRI device and the radiotherapy device and processes data received from the MRI device and the radiotherapy device. Alternatively, the processing device 120 may include at least two processing devices that can communicate with each other. One of the at least two processing devices may communicate with the MRI device and process data received from the MRI device, and the other may communicate with the radiotherapy device and process data received from the radiotherapy device. In some embodiments, the processing device 120 may include a treatment planning system.

[0051] In some embodiments, the processing device 120 can be a single server or a server group. The server group can be centralized or distributed. In some embodiments, the processing device 120 can be local or remote to the treatment device 110. For example, the processing device 120 can access information and / or data from the treatment device 110, the storage device 140 and / or the terminal device 150 via the network 130. For another example, the processing device 120 can be directly connected to the treatment device 110, the terminal device 150 and / or the storage device 140 to access information and / or data. In some embodiments, the processing device 120 can be implemented on a cloud platform. The cloud platform may include a private cloud, a public cloud, a hybrid cloud, a community cloud, a distributed cloud, a cloud-to-cloud cloud, a multi-cloud, etc. or any combination thereof.

[0052] The network 130 may include any suitable network that can facilitate information and / or data exchange of the radiation therapy system 100. In some embodiments, one or more components of the radiation therapy system 100 (e.g., the treatment device 110, the processing device 120, the storage device 140, or the terminal device 150) may communicate information and / or data with one or more other components of the radiation therapy system 100 through the network 130. For example, the processing device 120 may obtain image data from the treatment device 110 via the network 130. For another example, the processing device 120 may obtain user instructions from the terminal device 150 via the network 130. The network 130 may include a public network (e.g., the Internet), a private network (e.g., a local area network (LAN), a wide area network (WAN)), a wired network (e.g., Ethernet), a wireless network (e.g., an 802.11 network, a Wi-Fi network), 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 switch, a server computer, the like, or any combination thereof. In some embodiments, the network 130 may include one or more network access points. For example, the network 130 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 130 to exchange data and / or information.

[0053] The storage device 140 may store data, instructions, and / or any other information. In some embodiments, the storage device 140 may store data obtained from the treatment device 110, the processing device 120, and / or the terminal device 150. In some embodiments, the storage device 140 may store data and / or instructions executed by the processing device 120 or used to execute the exemplary methods described in this specification. In some embodiments, the storage device 140 may include a mass storage device, a removable storage device, a cloud-based storage device, a volatile read-write memory, a read-only memory (ROM), etc., or any combination thereof. Exemplary mass storage may include a magnetic disk, an optical disk, a solid-state drive, etc. Exemplary removable storage may include a flash drive, a floppy disk, an optical disk, a memory card, a compressed disk, a tape, etc. Exemplary volatile read-write memory may include a random access memory (RAM). Exemplary RAM may include dynamic RAM (DRAM), double data rate synchronous dynamic RAM (DDR-SDRAM), static RAM (SRAM), thyristor RAM (T-RAM), zero capacitance RAM (Z-RAM), etc. Exemplary ROMs may include mask ROM (MROM), programmable ROM (PROM), erasable programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), compact disk ROM (CD-ROM), digital versatile disk ROM, etc. In some embodiments, storage device 140 may be implemented on a cloud platform, as described elsewhere in this specification.

[0054] In some embodiments, the storage device 140 may be connected to the network 130 to communicate with one or more other components of the radiation therapy system 100 (e.g., the treatment apparatus 110, the processing device 120, or the terminal device 150). One or more components of the radiation therapy system 100 may access data or instructions stored in the storage device 140 through the network 130. In some embodiments, the storage device 140 may be part of the processing device 120.

[0055] The terminal device 150 can be connected and / or communicated with the treatment device 110, the processing device 120 and / or the storage device 140. For example, the processing device 120 can obtain a scanning protocol from the terminal device 150. For another example, the terminal device 150 can obtain image data from the treatment device 110 and / or the storage device 140. In some embodiments, the terminal device 150 may include a mobile device 151, a tablet computer 152, a laptop computer 153, etc. or any combination thereof. In some embodiments, the mobile device 151 may include a mobile phone, a personal digital assistant (PDA), a gaming device, a navigation device, a point of sale (POS) device, etc. or any combination thereof. In some embodiments, the terminal device 150 may include an input device, an output device, etc. The input device may include a keyboard, a touch screen, a voice input, a cursor control device, a mouse, a trackball, an eye tracking input, a brain monitoring system, or any other similar input mechanism. The input information received by the input device may be sent to the processing device 120 via, for example, a bus for further processing. The output device may include a display, a speaker, a printer, etc. or any combination thereof. In some embodiments, the terminal device 150 may be part of the processing device 120.

[0056] This description is intended to illustrate, rather than limit the scope of this specification. Many alternatives, modifications and variations are apparent to those skilled in the art. The features, structures, methods and features of the exemplary embodiments described herein may be combined in various ways to obtain additional and / or alternative exemplary embodiments. For example, the storage device 140 may be a data storage device including a cloud computing platform (e.g., a public cloud, a private cloud, a community, a hybrid cloud, etc.). In some embodiments, the processing device 120 may be integrated into the treatment device 110. However, these variations and modifications do not depart from the scope of this specification.

[0057] Figure 2 is a flow chart of an exemplary method of applying therapeutic radiation in a radiation therapy system according to some embodiments of the present specification. In some embodiments, Figure 2 One or more operations of the process 200 shown may be performed at Figure 1 The radiation therapy system 100 shown is implemented in FIG. Figure 2 The process 200 shown in FIG. 1 may be stored in the storage device 140 in the form of instructions and executed by Figure 1 The operations of the illustrated process 200 presented below are intended to be illustrative. It should be noted that the process 200 may also be similarly implemented in the terminal device 150. In some embodiments, the process 200 may be completed by one or more additional operations not described, and / or may not require one or more operations discussed. In addition, Figure 2The order in which the operations of flow 200 are illustrated and described below is not intended to be limiting.

[0058] In 202 , the processing device 120 may acquire magnetic resonance imaging (MRI) data about a region of interest (ROI) of a subject (eg, a treatment region associated with a tumor) through an MRI apparatus.

[0059] In 204, the processing device 120 may reconstruct an MR image associated with at least a portion of the ROI based on the MRI data. Based on the MRI data, the MR image may be reconstructed as a distribution of atomic nuclei in the subject. During the image reconstruction process, different types of image reconstruction techniques may be used. Exemplary image reconstruction techniques may include Fourier reconstruction in parallel MRI, constrained image reconstruction, regularized image reconstruction, etc. or any combination thereof. The MR image may be used to determine information related to therapeutic radiation for the tumor. For example, the processing device 120 may determine the tumor area and / or the radiation dose based on the MR image.

[0060] In some embodiments, it may take at least several minutes to reconstruct an MR image representing a relatively large imaging area. In some embodiments, in order to generate an MR image in a relatively short period of time (e.g., per second), the processing device 120 may reconstruct an initial image representing a relatively small imaging area (e.g., at least a portion of the ROI) instead of an initial image representing an MR image of a relatively large imaging area, and then combine the initial image with the MR image representing the relatively large imaging area. For example, the processing device 120 may replace a portion of the MR image representing a relatively large imaging area associated with the ROI with the initial image. The MR image representing the relatively large imaging area may include information of a non-ROI (e.g., healthy tissue) near the ROI and information of the ROI. In some embodiments, an MR image representing a relatively large imaging area may be acquired and reconstructed before therapeutic radiation is applied to a tumor. For example, an MR image representing a relatively large imaging area may be acquired for a period of time before a radiation source starts emitting a radiation beam for treatment, for example, less than 1 day, half a day, 6 hours, 3 hours, 1 hour, 45 minutes, 30 minutes, 20 minutes, 15 minutes, 10 minutes, 5 minutes, etc. In some embodiments, an MR image representing a relatively large imaging region may be obtained from a storage device (eg, storage device 140 ) in radiation therapy system 100 .

[0061] In 206, the processing device 120 may determine a parameter associated with the size of at least a portion of the ROI based on the MR image. In some embodiments, the parameter associated with the size of at least a portion of the ROI may include the size of a cross section of the tumor having a maximum area and perpendicular to the direction of the radiation beam irradiated on at least a portion of the ROI. In some embodiments, the parameter associated with the size of at least a portion of the ROI may indicate the shape of the cross section of the tumor. For example, the parameter associated with the size of at least a portion of the ROI may indicate that the shape of the cross section of the tumor is a circle, and further indicates the diameter of the circle. In some embodiments, in order to determine the parameter associated with the size of at least a portion of the ROI, the processing device 120 may extract texture information from the MR image, and determine a texture feature indicating the ROI by identifying frequent texture patterns of the ROI in the extracted texture information. Then, the processing device 120 may measure the size of the region including the texture feature in the MR image, and determine the parameter associated with the size of at least a portion of the ROI.

[0062] In 208, the processing device 120 may generate a control signal based on a parameter associated with a size of at least a portion of the ROI. The control signal may be dynamically adjusted based on at least two MR images taken at different points in time.

[0063] In some embodiments, the control signal may include one or more parameters associated with the therapeutic radiation on the tumor. For example, the control signal may include the radiation dose and the duration of the radiation beam. For another example, the control signal may include parameters associated with a multi-leaf collimator (MLC) that is used to determine the shape of the radiation beam projected onto the object. The MLC may include at least two separate leaves made of a high atomic number material (e.g., tungsten) that independently move in and out of the path of the radiation beam.

[0064] In some embodiments, the control signal may include one or more parameters associated with the movement of one or more components of the radiotherapy device. For example, the control signal may include parameters associated with one or more positions of a radiation source of the radiotherapy device. For another example, the control signal may include parameters associated with the height or position of a platform of the radiotherapy device to properly position the patient so that the patient's treatment area (e.g., a cancerous tumor or lesion) can properly receive the radiation beam from the radiotherapy device.

[0065] In 210, the processing device 120 may send a control signal to the radiotherapy device so that the radiotherapy device applies therapeutic radiation. During the therapeutic radiation, the radiation source of the radiotherapy device may rotate, during which the dose of radiation, the duration of the radiation beam, the shape of the MLC and / or the position of the platform may be changed. In some embodiments, the radiation beam is emitted only when the radiation source of the radiotherapy device is rotated to a specific angle (e.g., 60 degrees, 120 degrees, 180 degrees, 240 degrees, 300 degrees, 360 degrees). For example, intensity modulated radiation therapy (IMRT) may be applied. The radiation source may stop rotating intermittently. The radiation source may rotate to a desired position, pause at that position, emit a radiation beam, and then resume rotation. In some embodiments, the radiation source may rotate continuously and emit a radiation beam continuously or intermittently. In some embodiments, the radiation source may emit a radiation beam continuously while rotating.

[0066] It should be noted that the above description is provided for illustrative purposes only and is not intended to limit the scope of this specification. For those of ordinary skill in the art, various changes and modifications can be made according to the description of this specification. However, these changes and modifications do not depart from the scope of this specification. For example, operation 202 and operation 204 can be performed simultaneously. For another example, one or more other optional operations (e.g., storage operations) can be added to other locations of process 200. In the storage operation, information and / or data (e.g., MRI data, MR images, control signals) associated with therapeutic radiation can be stored in a storage device (e.g., storage device 140) disclosed elsewhere in this specification.

[0067] Figure 3-A is a schematic diagram of an exemplary treatment device according to some embodiments of the present specification. Figure 3-A As shown, the treatment device 110 may include an MRI device 310, a radiotherapy device 320, and a treatment couch 330. In some embodiments, as described in conjunction with process 200, the MRI device 310 may generate MRI data, and the radiotherapy device 320 may apply treatment radiation based on the MRI data.

[0068] The MRI device 310 may include a bore 311, a magnet 312, one or more gradient coils (not shown), and one or more radio frequency (RF) coils (not shown). The MRI device 310 may be configured to generate image data by scanning a region of interest (ROI) of the object (e.g., a treatment area associated with a tumor). In some embodiments, depending on the type of the magnet 312, the MRI device 310 may be a permanent magnet MRI scanner, a superconducting electromagnetic MRI scanner, a resistive electromagnetic MRI scanner, etc. In some embodiments, depending on the magnetic field strength, the MRI device 310 may be a high field MRI scanner, a mid-field MRI scanner, a low field MRI scanner, etc. In some embodiments, the type of the MRI device 310 may be a closed-bore (cylindrical) type, an open-bore type, etc.

[0069] The magnet 312 may have a ring shape and may generate a static magnetic field (eg, a main magnetic field) B0. The magnet 312 may be of various types, including, for example, a permanent magnet, a superconducting electromagnet, a resistive electromagnet, etc. The superconducting electromagnet may include niobium, vanadium, technetium alloy, etc.

[0070] One or more gradient coils may generate gradient magnetic fields to the main magnetic field B0 in the X, Y and / or Z directions (or axes). In some embodiments, one or more gradient coils may include an X-direction (or axis) coil, a Y-direction (or axis) coil, a Z-direction (or axis) coil, and the like. For example, the Z-direction coil may be designed based on a circular (Maxwell) coil, and the X-direction coil and the Y-direction coil may be designed based on a saddle (Golay) coil configuration. As used herein, the X-direction may also be referred to as a readout (RO) direction (or frequency encoding direction), the Y-direction may also be referred to as a phase encoding (PE) direction, and the Z-direction may also be referred to as a layer selection encoding direction. In this specification, the readout direction and the frequency encoding direction may be used interchangeably.

[0071] As an example only, the gradient magnetic field may include a slice selection gradient field corresponding to the Z direction, a phase encoding (PE) gradient field corresponding to the Y direction, a readout (RO) gradient field corresponding to the X direction, etc. Gradient magnetic fields in different directions can be used to encode spatial information of MR signals. In some embodiments, the gradient magnetic field can also be used to perform at least one function of flow encoding, flow compensation, flow phase dispersion, etc., or any combination thereof.

[0072] One or more radio frequency coils may transmit RF pulses to an object under examination (e.g., a body, a substance) and / or receive MR signals from the object under examination. As used herein, RF pulses may include excitation RF pulses and refocusing RF pulses. In some embodiments, an excitation RF pulse (e.g., a 90-degree RF pulse) may cause a magnetization vector to deviate from the direction of the main magnetic field B0. In some embodiments, a refocusing pulse (e.g., a 180-degree RF pulse) may rotate a dispersion spin isochromatic line around an axis in a transverse plane so that the magnetization vector may be rephased later. In some embodiments, the RF coil may include an RF transmitting coil and an RF receiving coil. The RF coil may transmit an RF pulse signal that may excite a cell nucleus in an object to resonate at a Larmor frequency. The RF receiving coil may receive MR signals transmitted from the object. In some embodiments, the RF transmitting coil and the RF receiving coil may be integrated into one coil, e.g., a transmitting / receiving coil. The RF coil may be one of various types, including, for example, a quotient difference (QD) orthogonal coil, a phased array coil, and the like. In some embodiments, different RF coils may be used to scan different parts of the body being examined, such as a head coil, a knee coil, a cervical spine coil, a thoracic spine coil, a temporomandibular joint (TMJ) coil, etc. In some embodiments, the RF coil may be classified into a volume coil and a local coil according to the function and / or size of the RF coil. For example, the volume coil may include a birdcage coil, a transverse electromagnetic coil, a surface coil, etc. For another example, the local coil may include a solenoid coil, a saddle coil, a flexible coil, etc.

[0073] The radiotherapy device 320 may include a radiation source (not shown), a roller 321, and a base 322. The radiation source may be configured to emit a radiation beam (also referred to as "radiation") to the treatment area in the hole 311. The radiation beam may be an X-ray beam, an electron beam, a gamma ray source, a proton ray source, etc. In some embodiments, the radiation source may generate the radiation beam according to one or more parameters (e.g., parameters of the radiation beam, parameters of the radiation source, etc.). The parameters of the radiation beam may include irradiation intensity, irradiation angle, irradiation distance, irradiation area, irradiation time, intensity distribution, etc., or any combination thereof. The parameters of the radiation source may include the position, rotation angle, rotation speed, rotation direction, configuration, etc., or any combination thereof of the radiation source. In some embodiments, during the generation of the radiation beam by the radiation source, the energy loss of the radiation beam caused by the magnet 312 (which may absorb at least a portion of the radiation beam) located in the path of the radiation beam may be considered. For example, the irradiation intensity of the radiation beam may be set to be greater than the irradiation intensity in the absence of energy loss (e.g., due to absorption by the magnet 312), thereby compensating for the energy loss so that a radiation beam of a specific intensity may hit the treatment area (e.g., a tumor).

[0074] The drum 321 may have a ring shape. The drum 321 may be arranged around the magnet 312 and intersect the magnet 312 at a central region of the magnet 312 along the axis 340 of the hole 311. The drum 321 may accommodate and support the radiation source. The drum 321 together with the radiation source mounted thereon may rotate around the axis 340 of the hole 311 and / or a point called the “isocenter”. By way of example only, the drum 321 together with the radiation source mounted thereon may rotate around the axis 340 at any angle, such as 90 degrees, 180 degrees, 360 degrees, 450 degrees, 540 degrees, etc. The drum 321 may be further supported by the base 322.

[0075] The treatment couch 330 may include a platform 331 and a base 332. In some embodiments, the platform 331 may move in a horizontal direction and enter the bore 311 of the MRI device 310. In some embodiments, the platform 331 may move in two, three, four, five, or six dimensions. In some embodiments, the platform 331 may move according to changes (e.g., position changes) of a tumor estimated, for example, based on real-time MR images obtained during treatment.

[0076] In some embodiments, the object may be placed on the platform 331 and sent to the MRI apparatus 310. In some embodiments, the object may be a human patient. The human patient may lie on the platform 331 in a supine, prone, or side position.

[0077] During treatment, the roller 321 can be configured to rotate around the magnet 312. In some embodiments, the magnet 312 can include grooves (not shown) at its outer wall. The grooves can be arranged around the entire circumference of the magnet 312. For example, the grooves can have the shape of an annular space surrounding the magnet 312, thereby accommodating at least a portion of the roller 321. In some embodiments, the grooves can be arranged around a portion of the circumference of the magnet 312. For example, the grooves can have the shape of an arc surrounding the magnet 312. Further description of the treatment device 110 can be found elsewhere in this specification (e.g., Figure 4 and its description).

[0078] It should be noted that the above description of the treatment device 110 is for illustrative purposes only and is not intended to limit the scope of the present specification. For those skilled in the art, various changes or modifications can be made under the guidance of the present specification. However, these changes and modifications do not depart from the scope of the present specification.

[0079] Figure 3-B is a schematic diagram of another exemplary therapeutic device according to some embodiments of the present specification. Figure 3-ACompared with the treatment device 110 described in the above, the treatment device 110' can use a frame 321' instead of a roller 321. The frame 321' can be set on one side of the magnet 312. The treatment head 323 can be mounted on the frame 321' through the treatment arm 324. The treatment head 323 can accommodate a radiation source. The frame 321' can rotate the treatment head 323 around the axis 340 of the hole 311.

[0080] like Figure 3-B As shown, the groove 325 may be formed at the outer wall of the magnet 312 and have an annular shape. The groove 325 may accommodate at least a portion of the treatment head 323 and provide a path for the treatment head 323 to rotate. This arrangement may reduce the distance between the treatment head 323 and the axis 340 of the hole 311 along the radial direction of the magnet 312. In some embodiments, the reduction in the distance between the treatment head 323 and the axis 340 of the hole 311 may increase the radiation dose reaching the treatment area (e.g., an area including a tumor), thereby improving the treatment efficiency. In some embodiments, the width of the groove 325 along the Z direction (i.e., the axial direction of the magnet 312) may not be less than the width of the treatment head 323 along the Z direction.

[0081] It should be noted that the above description of the treatment device 110' is for illustrative purposes only and is not intended to limit the scope of the present specification. For those of ordinary skill in the art, various changes and modifications can be made based on the description of the present specification. However, these changes and modifications do not depart from the scope of the present specification. For example, the assembly and / or function of the treatment device 110 may be changed or altered according to a specific embodiment. In some embodiments, the magnet 312 of the MRI device 310 may also rotate relative to the treatment head 323. For example, the radiotherapy device 320 and the MRI device 310 can rotate synchronously or asynchronously around the same axis (e.g., axis 340).

[0082] Figure 4 is a schematic diagram of an upper portion of a cross-section of an exemplary treatment device viewed along the X direction according to some embodiments of the present specification.

[0083] As combined Figure 3-A or Figure 3-B As described above, the MRI device 310 may further include at least two main magnetic coils 401 , at least two shielding magnetic coils 402 , and a cryostat 403 .

[0084] In some embodiments, the cryostat 403 may be shaped as an annular space along the axis 340. At least two main magnetic coils 401 and at least two shielding magnetic coils 402 may be housed in the cryostat 403 and maintain a superconducting state under certain conditions (e.g., conditions when both the main magnetic coils and the shielding magnetic coils are incorporated in a cooling medium in the cryostat 403). In some embodiments, the at least two main magnetic coils 401 may be coaxially arranged along the axis 340, and the at least two shielding magnetic coils 402 may also be coaxially arranged along the axis 340 at a larger radius than the at least two main magnetic coils 401. In some embodiments, the at least two main magnetic coils 401 may carry current in a first direction and generate a uniform magnetic field (e.g., a main magnetic field B0) in a specific region (e.g., a region within the hole 311); the at least two shielding coils 402 may carry current in a second direction opposite to the first direction and help shield the magnetic field generated by the at least two main magnetic coils 401 in a region outside the MRI device 310.

[0085] In some embodiments, the cryostat 403 may include two chambers (e.g., a left chamber 403a and a right chamber 403b) located at opposite sides of the cryostat 403 along the axis 340 and connected to each other by a neck 403c, wherein the radius of the neck 403c is smaller than the radius of the two chambers. In some embodiments, each of the two chambers may accommodate at least one of the at least two main magnetic coils 401 and at least one of the at least two shielding magnetic coils 402. A gap 406 may be formed between the main magnetic coil disposed in the left chamber 403a and the main magnetic coil disposed in the right chamber 403b, thereby allowing the radiation beam generated by the radiotherapy device 320 to pass through.

[0086] In addition, the cryostat 403 may include a groove 408 located at a radial position between the two chambers, which is in the shape of an annular groove. The groove 408 may include an opening 407 formed between the outer surfaces of the two chambers. The depth of the groove 408 (i.e., the distance between the outer surface of the neck 403c and the outer surfaces of the two chambers) and the width of the groove 408 (i.e., the dimension in the axial direction) may be the default settings of the radiotherapy system 100, or may be adjusted in different situations. For example, the width of the groove 408 may be adjusted for different radial positions.

[0087] As combined Figure 3-A or Figure 3-B As described above, the radiotherapy apparatus 320 may further include an accelerator 409 , a target 410 , a primary collimator 411 , and a multi-leaf collimator (MLC) 412 accommodated in the recess 408 .

[0088] The accelerator 409 may be configured to accelerate charged subatomic particles or ions to high speeds. In some embodiments, the accelerator 409 may accelerate electrons using microwave technology. For example, the accelerator 409 may use high RF electromagnetic waves to accelerate electrons in an electron beam having an energy group between 4 MeV and 22 MeV. The accelerator 409 may rotate about the axis 340 and may enable the radiation beam to be emitted from any circumferential position. The accelerator 409 may include an accelerating waveguide (tube) whose axis is perpendicular to the axis 340. The accelerating waveguide (tube) may provide a linear path for accelerating electrons along a beam path perpendicular to the axis 340.

[0089] Target 410 may be configured to receive accelerated charged subatomic particles or ions (e.g., an electron beam) to produce a radiation beam for therapeutic radiation. For example, the electron beam may collide with target 410 to produce high-energy X-rays based on the bremsstrahlung effect. In some embodiments, target 410 may be located near the exit window of accelerator 409 to receive the accelerated electron beam. In some embodiments, target 410 may be made of a material including aluminum, copper, silver, tungsten, etc., or any combination thereof. Alternatively, target 410 may be made of a composite material including tungsten and copper, tungsten and silver, tungsten and aluminum, etc., or any combination thereof. The radiation beam from target 410 may pass through a primary collimator 411 to form a beam of light having a specific shape (e.g., a cone beam).

[0090] The MLC 412 can be configured to shape the radiation beam. For example, the MLC 412 can adjust the irradiation shape or irradiation area of ​​the radiation beam. The MLC 412 can be placed at any position on the path of the radiation beam. For example, the MLC 412 can be placed close to the accelerator 409. Therefore, the radiation beam shaped by the MLC 412 can further pass through the neck 403c of the cryostat 403 and the gap 406 between at least two main magnetic coils 401 to reach the treatment area. For another example, the MLC 412 can be placed at a relatively long distance from the accelerator 409 so that the MLC 412 can be closer to the patient to be irradiated. In some embodiments, the MLC 412 may include at least two independent blades made of a high atomic number material (e.g., tungsten) that independently move in and out of the path of the radiation beam to block the radiation beam. When at least two separate blades move in and out, the shape of the radiation beam can change to form different slots, simulating the movement of the radiation beam from the axis (i.e., Figure 4 A cross section of a tumor observed as shown in FIG. 4 (dashed line 404).

[0091] It should be noted that the above description of the treatment device 110' is for illustrative purposes and not for limiting the scope of the present specification. For those of ordinary skill in the art, various changes and modifications can be made according to the description of the present specification. However, these changes and modifications do not depart from the scope of the present specification. For example, at least a portion of the radiotherapy device 320 may be located outside the groove 408 along the radial direction of the cryostat 403. For another example, the left chamber 403a and the right chamber 403b may be isolated from each other, and the neck portion 403c may be unnecessary. More descriptions of the treatment device 110 can be found in International Application No. PCT / CN2018 / 115394 filed on November 14, 2018 and International Application No. PCT / CN2019 / 074540 filed on February 2, 2019, the entire contents of which are incorporated herein by reference.

[0092] Figure 5-A 3 is a schematic diagram of a perspective view of an exemplary treatment device according to some embodiments of the present specification. As described in other parts of the present specification, during the operation of the MRI device 310 and the radiotherapy device 320, interference may be generated, such as magnetic interference generated by the MRI device 310, RF interference generated by the MRI device 310, microwave interference generated by the radiotherapy device 320, etc. In order to reduce interference, the radiotherapy device 110 may include a shielding device of at least one shielding structure.

[0093] like Figure 5-A As shown, the shielding device may include at least one shielding structure (e.g., 510, 520, 530, 540), and the accelerator 409 may be at least partially surrounded by the at least one shielding structure. In some embodiments, the shielding device may be mounted on a portion of the frame 321' or the drum 321. In some embodiments, the at least one shielding structure may correspond to at least one block occupying at least a portion of the frame 321' or the drum 321, respectively. In some embodiments, the at least one shielding structure may be accommodated in the groove 408, or may extend from the groove 408.

[0094] In some embodiments, each of the at least one shielding structure may have a shape similar to the symbol “I”, which may provide a continuous path for the magnetic field to pass along the axial direction of the cryostat 403 (i.e., the direction of the axis 340). In some embodiments, the at least one shielding structure may include at least one pair of shielding structures (e.g., one pair includes 510 and 520, and one pair includes 530 and 540), which are located at opposite positions along the circumferential direction of the groove 408 and are symmetrical to each other.

[0095] Taking a pair including 510 and 520 as an example, the shielding structure 510 and the shielding structure 520 are located on opposite sides of the accelerator 409 along the circumferential direction of the groove 408, and then the magnetic field generated by the MRI device 310 can be conducted by the pair of shielding structures and can be maintained from the area formed between them, thereby achieving the magnetic field shielding effect of the accelerator 409. In some embodiments, the shielding structure 510 and the shielding structure 520 can be radially arranged around the axis 340, and at least one side of each shielding structure can point to the axis 340. In some embodiments, the shielding structure 510 and the shielding structure 520 can be connected to each other along the axial direction of the cryostat 403 on both sides of the accelerator 409, thereby forming a closed loop around the accelerator 409. In some embodiments, the shielding structure 510 and the shielding structure 520 can be separated from each other along the axial direction of the cryostat 403 on both sides of the linear accelerator 409, thereby forming a semi-closed loop substantially around the accelerator 409.

[0096] In some embodiments, shielding structures 510 and 520 present in the magnetic field of MRI device 310 may exert an influence on the magnetic field (e.g., deform the distribution and cause the magnetic field to be non-uniform). In order to correct the magnetic field deformation caused by shielding structures 510 and 520, similar shielding structures (e.g., shielding structures 530 and 540) may also be placed in recess 408.

[0097] In some embodiments, the shielding structures can be identical to each other. For example, the shielding structures can be made of the same material and have the same structure. In some embodiments, at least one pair of shielding structures can be placed at a preset symmetrical circumferential position around the axis 340. For example, at least one pair of shielding structures can be evenly distributed in the groove 408.

[0098] Figure 5-B is a schematic diagram of a perspective view of another exemplary therapeutic device according to some embodiments of the present specification.

[0099] like Figure 5-B As shown, at least one shielding structure may include a shielding structure 550 and a shielding structure 560 located between two chambers of the cryostat 403, and multiple shielding structures (e.g., 571, 572, 573, 574, 575, 576) located between the shielding structure 550 and the shielding structure 560.

[0100] Specifically, shielding structure 550 and shielding structure 560 may both have a ring shape and may be parallel to each other and coaxial with hole 311. The outer diameter of shielding structure 550 and / or shielding structure 560 may be greater than or equal to the outer diameter of cryostat 403; the inner diameter of shielding structure 550 and / or shielding structure 560 may be greater than or equal to the inner diameter of cryostat 403; the difference between the outer diameter and the inner diameter of shielding structure 550 and / or shielding structure 560 may be greater than or equal to the longitudinal length of accelerator 409.

[0101] Further, each of a plurality of shielding structures (e.g., 571, 572, 573, 574, 575, 576) located between shielding structure 550 and shielding structure 560 may be connected to shielding structure 550 and shielding structure 560, and adjacent shielding structures of at least two shielding structures may form a magnetic shielding structure with a portion of shielding structure 550 and a portion of shielding structure 560. Accelerator 409 may be located within any magnetic shielding structure.

[0102] In some embodiments, the at least two shielding structures may be evenly or unevenly distributed between shielding structure 550 and shielding structure 560. In some embodiments, the count of the at least two shielding structures may be a multiple of 2, forming an even number of magnetic shielding structures, thereby reducing the inhomogeneity of the magnetic field caused by the presence of the at least two shielding structures.

[0103] As combined Figure 5-A As described above, the shielding structure 550, the shielding structure 560, and at least two shielding structures (eg, 571, 572, 573, 574, 575, 576) located between the shielding structure 550 and the shielding structure 560 may form Figure 5-A For example, a portion of shield structure 550, a portion of shield structure 560, shield structure 575, and shield structure 576 may form a magnetic shield structure similar to the magnetic shield structure formed by shield structure 510 and shield structure 520.

[0104] It should be noted that the above description of the shielding structure is for illustrative purposes only and is not intended to limit the scope of this specification. For those of ordinary skill in the art, various changes and modifications can be made according to the description of this specification. However, these changes and modifications do not depart from the scope of this specification. For more description of the shielding structure, please refer to International Application No. PCT / CN2018 / 115394 filed on November 14, 2018 and International Application No. PCT / CN2019 / 074540 filed on February 2, 2019, the entire contents of which are incorporated herein by reference.

[0105] Figure 6FIG. 1 is a schematic diagram of an exemplary eddy current on a shielding structure according to some embodiments of the present specification. Figure 5-A or Figure 5-B As described above, during operation of the treatment device 110, the shielding structure may rotate with the frame 321' or the drum 321 around the axis 340, during which the magnetic field lines of the magnetic field generated by the MRI device 310 may be cut by the shielding structure, and eddy currents may be generated on the shielding structure. Taking a specific shielding structure as an example, Figure 6 As shown, at least two eddy currents (each eddy current forms a current loop (collectively referred to as current loop E)) on a specific shielding structure obtained by simulating the operation of the treatment device 110 can be seen.

[0106] In some embodiments, the intensity of the eddy current may be related to the magnetic field parameters of the MRI device 310 (e.g., magnetic field strength, magnetic field direction), the material parameters of the shielding structure (e.g., magnetic permeability, electrical conductivity, resistivity), the distance between the MRI device 310 and the shielding structure (e.g., the distance between the shielding structure and the shaft 340), the rotation speed of the frame 321' or the drum 321, etc. or any combination thereof. For example, the greater the rotation speed of the frame 321' or the drum 321, the higher the eddy current intensity generated on the shielding structure may be. For another example, the higher the magnetic field intensity of the MRI device 310, the higher the eddy current intensity generated on the shielding structure. For another example, the lower the electrical conductivity of the shielding structure, the lower the intensity of the eddy current generated on the shielding structure. For another example, the shorter the distance between the MRI device 310 and the shielding structure, the higher the eddy current intensity generated on the shielding structure.

[0107] Figure 7 is a schematic diagram of an exemplary vortex reduction device according to some embodiments of the present specification. Figure 6 As described above, due to the presence of eddy currents on the shielding structure, an eddy current magnetic field may be generated based on the eddy currents, which may affect the magnetic field of the MRI device 310 and then affect the image quality of the MR image generated by the MRI device 310. In order to reduce the influence of the eddy currents, an eddy current reducing device may be included in the radiotherapy device 320.

[0108] like Figure 7 As shown, the vortex reducer 700 may include at least one structure (e.g., 721, 722, 723, 724). In some embodiments, the vortex reducer 700 may be coupled to the frame 321' or the drum 321. In some embodiments, the vortex reducer 700 may be a part of the frame 321' or the drum 321. In some embodiments, each of the at least one structure may correspond to a block that occupies at least a portion of the frame.

[0109] In some embodiments, such as in combination Figure 5-A or Figure 5-BAs described above, the eddy current reducing device 700 can be manufactured based on the shielding device. Figure 7 As shown, each of the at least one structure may correspond to a corresponding shielding structure included in the shielding device and may be manufactured by partially or entirely modifying the shielding structure.

[0110] In some embodiments, as described elsewhere in the present invention, at least one shielding structure of the shielding device can be used to reduce the magnetic interference generated by the MRI device 310 to the radiotherapy device 320, and accordingly, the characteristics of the shielding structure (e.g., size, shape, thickness, configuration) can be associated with the shielding parameters of the radiotherapy device 320 (e.g., shielding effect, such as the degree of shielding relative to magnetic interference). As used herein, the shielding parameters can be related to the magnetic field of the MRI device 310 (e.g., magnetic field strength, magnetic field direction, magnetic field configuration). Therefore, for at least one of the at least one structure that can be manufactured based on the at least one shielding structure, the corresponding characteristics of the structure (e.g., size, shape, thickness, configuration) can also be associated with the shielding parameters of the radiotherapy device 320. For example, the size, thickness and / or shape of the shielding structure and / or the size, thickness and / or shape of the structure can be associated with the magnetic field strength of the MRI device 310 (e.g., the strength of the main magnetic field B0). For another example, the at least one shielding structure and / or the at least one structure can be placed at a preset symmetrical circumferential position around the axis 340 to correct the magnetic field deformation caused by the shielding structure or the structure.

[0111] In some embodiments, the at least one structure (or the at least one shielding structure) may be made of a material having a relatively high magnetic permeability, a relatively low electrical conductivity, and a relatively high resistivity, which may provide a shielding effect and an eddy current reduction effect. For example, the at least one structure may be made of a manganese-zinc ferrite material or a powder metallurgy material.

[0112] In some embodiments, at least one of the at least one structure may include at least two internal structures (e.g., Figure 7 The internal structure represented by the solid line shown in the figure), wherein at least some of the at least two internal structures are electrically disconnected from each other. In some embodiments, taking a specific structure as an example, the at least two internal structures can be obtained by dividing a specific shielding structure corresponding to the specific structure.

[0113] In some embodiments, any of the at least two internal structures may include a plate, slice, piece, particle, strip, segment, or any irregular structure. By way of example only, the at least two internal structures may include at least two plates. In some embodiments, for at least one of the at least one structure, the thickness of the at least two plates is uniform or substantially uniform. As used herein, "substantially uniform" means that the difference between the thickness of any two plates is less than a predetermined threshold.

[0114] In some embodiments, for at least one of the at least one structure, an electrically insulating material (e.g., an insulating coating) may be present between at least one pair of adjacent internal structures (e.g., adjacent plates) of the at least two internal structures. In some embodiments, the at least two internal structures may be coated with an electrically insulating material and pressed together.

[0115] In some embodiments, for at least one of the at least one structure, a gap may exist between at least one pair of adjacent internal structures of the at least two internal structures. In some embodiments, the gap may be empty. In some embodiments, the gap may be partially or completely filled with an electrically insulating material. The electrically insulating material or the gap between at least one pair of adjacent internal structures of the at least two internal structures may block the electrical connection between the at least one pair of adjacent internal structures and the eddy current conduction on the structure (i.e., the simulated eddy current obtained by the operation of the simulated treatment device 110), thereby reducing the eddy current intensity corresponding to the structure.

[0116] In some embodiments, for at least one of the at least one structure, the plurality of internal structures (e.g., the plates) may be arranged in a direction that disconnects a current loop that simulates an eddy current corresponding to the structure generated in response to the magnetic field of the MRI device 310. More descriptions about the arrangement of at least two internal structures may be found elsewhere in this specification (e.g., Figure 8 to Figure 9-D and its description).

[0117] In some embodiments, for at least one of the at least one structures, a structural parameter of the structure may be associated with a simulated eddy current intensity corresponding to the structure in response to the magnetic field of the MRI device 310. The structural parameter of the structure may include the number of at least two internal structures (e.g., plates) in the structure or the thickness of at least two internal structures included in the structure. Figure 6 As described in the operation, the simulated eddy current intensity may be related to the magnetic field parameters (e.g., magnetic field intensity, magnetic field direction) of the MRI device 310, the material parameters (e.g., magnetic permeability, electrical conductivity, resistivity) of the structure, the distance between the MRI device 310 and the structure, the rotation speed of the frame 321' or the drum 321, etc. or any combination thereof. For example, the higher the simulated eddy current intensity corresponding to the structure, the greater the number of the at least two internal structures may be. For another example, the higher the simulated eddy current intensity corresponding to the structure, the smaller the thickness of the at least two internal structures may be.

[0118] In some embodiments, at least one structure included in the eddy current reducing device can be dynamically adjusted based on the rotation speed of the frame 321' or the drum 321. As described in other parts of this specification, the simulated eddy current intensity corresponding to the structure can vary with the rotation speed of the frame 321' or the drum 321, and therefore, the at least one structure can be dynamically adjusted based on the simulated eddy current intensity corresponding to the structure. For example, when the simulated eddy current intensity corresponding to the structure is greater than a predetermined threshold, at least two internal structures having a relatively large thickness included in the structure can be automatically replaced by at least two internal structures having a relatively small thickness.

[0119] It should be noted that the above description is for illustrative purposes only and is not intended to limit the scope of the present specification. For those of ordinary skill in the art, various changes and modifications can be made according to the description of this specification. However, these changes and modifications do not depart from the scope of this specification. For example, in addition to or in contrast to at least one of the above structures, the eddy current reduction device 700 may include at least one block, the at least one block may include at least two conductors, at least some of the at least two conductors being electrically disconnected from each other.

[0120] Figure 8 is a schematic diagram of an exemplary arrangement of at least two internal structures included in the structure of the vortex reducing device according to some embodiments of the present specification. Figure 6 As described above, at least two eddy currents (ie, simulated eddy currents) can form at least two current loops on the specific shielding structure.

[0121] Taking the specific structure 810 of the eddy current reducing device 700 corresponding to the specific shielding structure as an example, Figure 8 As shown, in order to reduce eddy current interference, at least two internal structures (e.g., 811, 812, 813, 814, 815, 816) included in a specific structure can be arranged along the direction of disconnecting the current loop of the simulated eddy current corresponding to the structure. Under this arrangement, at least two internal eddy currents can be generated on each of the at least two internal structures included in the structure 810, and each of the at least two internal eddy currents forms an internal current loop (e.g., collectively referred to as E1, E2, E3, E4, E5, E6). It can be seen that the current loop E is disconnected by at least two internal structures, and at least two internal current loops are generated on at least two internal structures. In addition, the total intensity of the sum of the internal eddy currents is lower than the eddy current intensity corresponding to the entire structure, thereby reducing eddy current interference.

[0122] Figure 9-A to Figure 9-D is a schematic diagram of an exemplary internal structure included in the structure of a vortex reducing device according to some embodiments of the present specification.

[0123] like Figure 9-AAs shown, at least two internal structures may include at least two plates with uniform thickness. In addition, electrical insulating material 901 exists between two adjacent plates (e.g., plate 911 and plate 912) of the at least two plates, which can block the electrical connection between the adjacent plates and accordingly cut off the current loop simulating eddy current on the structure.

[0124] like Figure 9-B As shown, the thickness of at least two plates is also uniform. In addition, there is a gap 902 between two adjacent plates (e.g., plate 921 and plate 922) of at least two plates, instead of an electrically insulating material 901. In some embodiments, the gap may be partially or completely filled with any electrically insulating material. In some embodiments, an electrically insulating connecting medium (e.g., an insulating wire, an insulating bracket) may be present in the gap. In some embodiments, the gap may be empty.

[0125] like Figure 9-C As shown, the thickness of at least two plates is not completely uniform. It can be seen that the thickness of some of the at least two plates is relatively large, while the thickness of other plates is relatively small. In some embodiments, the closer to the hole 311, the smaller the thickness of the plate.

[0126] like Figure 9-D As shown, at least two internal structures (eg, plates) exist in a portion of the structure (eg, a portion near the hole 311), and the remainder of the structure remains an entire block structure.

[0127] Figure 10-A is a schematic diagram of exemplary eddy current intensities associated with a radiation therapy apparatus without an eddy current reducing device according to some embodiments of the present specification. Figure 10-B is a schematic diagram of exemplary eddy current intensities associated with a radiotherapy apparatus having an eddy current reducing apparatus according to some embodiments of the present specification.

[0128] As combined Figure 4 As stated, Figure 10-A or Figure 10-B As shown, at least two main magnetic field coils 401 and at least two shielding coils 402 may be coaxially arranged along an axis (eg, axis 340). Figure 10-A As shown, the shielding structure 1001 of the shielding device is arranged above the coil of the MRI device 310; Figure 10-B As shown, the structure 1002 of the eddy current reducing device is arranged above the coil of the MRI device 310. As described elsewhere in this specification, the structure 1002 may correspond to the shielding structure 1001 and may be obtained by dividing the shielding structure 1001.

[0129] According to the simulation of the operation of the treatment device 110, the simulated eddy current on the shielding structure 1001 or the structure 1002 can be obtained. It can be seen that the gray scale of the shielding structure 1001 is lower than the gray scale of the structure 1002, which indicates that the eddy current on the structure 1002 is lower than the eddy current on the shielding structure 1001.

[0130] The basic concepts have been described above. Obviously, for those of ordinary skill in the art who have read this application, the above invention disclosure is only for example and does not constitute a limitation of this specification. Although not explicitly stated here, those of ordinary skill in the art may make various modifications, improvements and amendments to this specification. Such modifications, improvements and amendments are suggested in this specification, so such modifications, improvements and amendments still belong to the spirit and scope of the exemplary embodiments of this specification.

[0131] At the same time, this specification uses specific words to describe the embodiments of this specification. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of this specification. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different positions in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures or characteristics in one or more embodiments of this specification can be appropriately combined.

[0132] In addition, it will be understood by those skilled in the art that various aspects of this specification may be illustrated and described by a number of patentable categories or situations, including any new and useful process, machine, product, or combination of substances, or any new and useful improvement thereof. Therefore, various aspects of this specification may be implemented entirely by hardware, software (including firmware, resident software, microcode, etc.), or a combination of software and hardware, which are generally referred to herein as "units", "modules", or "systems". In addition, various aspects of the invention may take the form of a computer program product embodied in one or more computer-readable media having computer-readable program code embodied thereon.

[0133] In addition, unless explicitly stated in the claims, the order of the processing elements and sequences described in this specification, the use of alphanumeric characters, or the use of other names are not intended to limit the order of the processes and methods of this specification. Although the above disclosure discusses some invention embodiments that are currently considered useful through various examples, it should be understood that such details are only for illustrative purposes, and the attached claims are not limited to the disclosed embodiments. On the contrary, the claims are intended to cover all modifications and equivalent combinations that are consistent with the essence and scope of the embodiments of this specification. For example, although the implementation of the various components described above can be embodied in a hardware device, it can also be implemented as a pure software solution, for example, installation on an existing server or mobile device.

[0134] Similarly, it should be noted that in order to simplify the description disclosed in this specification and thus facilitate the understanding of one or more embodiments of the invention, the foregoing description of the embodiments of this specification sometimes combines multiple features into one embodiment, figure, or description thereof. However, this method of the specification should not be interpreted as reflecting the intention that the claimed object material to be scanned requires more features than those explicitly stated in each claim. In fact, the features of the embodiments are less than all the features of the single embodiment disclosed above.

[0135] In some embodiments, numbers representing quantities or characteristics used to describe and claim certain embodiments of this specification should be understood to be modified by the terms "approximately", "approximately" or "substantially" in some cases. For example, "approximately", "approximately" or "substantially" may represent a ±20% variation of the value described, unless otherwise stated. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may vary depending on the characteristics required by individual embodiments. In some embodiments, numerical parameters should take into account the specified significant digits and adopt the general method of retaining digits. Although the numerical domains and parameters used to confirm the breadth of their range in some embodiments of this specification are approximate values, in specific embodiments, such numerical values ​​are set as accurately as possible within the feasible range.

[0136] All patents, patent applications, patent application publications, and other materials (such as papers, books, specifications, publications, records, things, and / or the like) referred to herein are hereby incorporated by reference in their entirety for all purposes, except any prosecution record related to such documents, any such documents that are inconsistent or conflicting with this document, or any such documents that have the effect of limiting the broad scope of the claims that may or may not be related to this document. For example, if there is any inconsistency or conflict between the description, definition, and / or use of terms associated with any incorporated material and the terminology associated with this document, the description, definition, and / or terminology used in this document shall control.

[0137] Finally, it should be understood that the embodiments described in this specification are only used to illustrate the principles of the embodiments of this specification. Other variations may also fall within the scope of this specification. Therefore, as an example and not a limitation, alternative configurations of the embodiments of this specification may be considered consistent with the teachings of this specification. Accordingly, the embodiments of this specification are not limited to the embodiments explicitly introduced and described in this specification.

Claims

1. A radiotherapy system, characterized in that: include: a magnetic resonance imaging (MRI) device configured to acquire magnetic resonance imaging data about a region of interest (ROI); as well as A radiotherapy device is configured to apply therapeutic radiation to at least a portion of the ROI, the radiotherapy device comprising a shielding device, the shielding device comprising two first shielding structures and a plurality of second shielding structures, the two first shielding structures having a ring shape, being parallel to each other and coaxial with the aperture of the radiotherapy device, the plurality of second shielding structures being located between the two first shielding structures and connected to the two first shielding structures.

2. The system according to claim 1, characterized in that At least a portion of the two first shield structures and the plurality of second shield structures are modified to include an eddy current reducing device, the eddy current reducing device includes at least two internal structures, and the at least two internal structures are electrically disconnected from each other.

3. The system according to claim 1, characterized in that The radiotherapy apparatus further includes an accelerator, which is at least partially surrounded by two adjacent second shielding structures.

4. The system according to claim 3, characterized in that The two first shielding structures and the plurality of second shielding structures are configured to reduce magnetic interference generated by an MRI device on the accelerator.

5. The system according to claim 1, characterized in that The count of the plurality of second shielding structures is a multiple of two.

6. The system according to claim 1, characterized in that The two first shielding structures are located between two chambers of the cryostat of the radiotherapy apparatus.

7. The system according to claim 6, characterized in that An outer diameter of at least one of the two first shielding structures is greater than or equal to an outer diameter of the cryostat.

8. The system according to claim 6, characterized in that An inner diameter of at least one of the two first shielding structures is greater than or equal to an inner diameter of the cryostat.

9. The system according to claim 2, characterized in that There is a gap between at least one pair of adjacent inner structures among the at least two inner structures, and the gap is empty or filled with an electrically insulating material.

10. A radiotherapy system comprising: a magnetic resonance imaging (MRI) device configured to acquire magnetic resonance imaging data about a region of interest (ROI); as well as A radiotherapy device is configured to apply therapeutic radiation to at least a portion of the ROI, the radiotherapy device comprising a shielding device and an accelerator, the shielding device comprising a plurality of shielding structure pairs, the plurality of shielding structure pairs are symmetrically arranged along the axial direction of a frame of the radiotherapy device, and each shielding structure pair surrounds at least a portion of the accelerator.

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