Radiation therapy system

Abstract

The system includes a magnetic resonance imaging (MRI) device (310) configured to acquire MRI data about a region of interest (ROI), and a radiation therapy device (300) configured to radiation therapy at least a portion of the region of interest.

Description

[0001] Description of the case

[0002] This application is a divisional application filed for the Chinese application with a filing date of November 14, 2018, application number 201880060517.6, and invention name “Radiotherapy System”. Technical Field

[0003] The present application relates generally to radiation therapy systems and, more particularly, to image-guided radiation therapy systems that combine radiation therapy and magnetic resonance imaging techniques. Background Art

[0004] Currently, radiation therapy for tumors is affected by the difficulty of tracking changes (e.g., movement) of the tumor during different treatments. Today, various imaging techniques can be used to provide real-time images of the tumor before or during each treatment period. For example, a magnetic resonance imaging (MRI) device can be used in conjunction with a radiotherapy device to provide an MRI image of the tumor. The combination of an MRI device and a radiotherapy device forms a treatment device, which may encounter difficulties when arranging the components of the MRI device (e.g., at least two main magnetic coils, at least two magnetic shielding coils) and in a relatively compact space where the radiotherapy device (e.g., a linear accelerator) does not cause interference. Therefore, it may be desirable to provide a treatment device that provides high treatment quality and also has a compact structure. Summary of the invention

[0005] The present application provides a radiotherapy system, which may include: a magnetic resonance imaging device, configured to acquire magnetic resonance imaging data about a region of interest, the magnetic resonance imaging device including: an annular cryostat, the annular cryostat including at least one outer wall and at least one inner wall coaxial with the axis of the annular cryostat, wherein the annular cryostat includes: an annular concave structure, the annular concave structure having an opening formed at at least one inner wall; and a radiotherapy device, configured to radiotherapy at least a portion of the region of interest, the radiotherapy device including: a multi-leaf collimator, the multi-leaf collimator being accommodated in the annular concave structure of the annular cryostat, and configured to control the shape of a photon beam of radiotherapy passing through the multi-leaf collimator.

[0006] In some embodiments, the multi-leaf collimator is configured to move along a sliding structure within the annular concave structure.

[0007] In some embodiments, the magnetic resonance imaging apparatus comprises: at least two main magnetic coils; at least two magnetic shielding coils; the at least two main magnetic coils and the at least two magnetic shielding coils are coaxially arranged along an axis of the annular cryostat, and the at least two magnetic shielding coils are arranged at a larger radius from the axis than the at least two main magnetic coils.

[0008] In some embodiments, one or more of the at least two main magnetic coils are arranged to surround the annular concave structure, and a radius of the one or more main magnetic coils from the axis is greater than a radius of the remaining main magnetic coils from the axis.

[0009] In some embodiments, the annular cryostat further comprises: an annular groove between the at least one outer wall and the at least one inner wall.

[0010] In some embodiments, the radiotherapy apparatus further comprises: a linear accelerator configured to accelerate electrons in the electron beam to generate a photon beam for radiotherapy, the linear accelerator being at least partially located within the annular recess of the cryostat.

[0011] In some embodiments, the multi-leaf collimator is connected to the linear accelerator via two or more rods.

[0012] In some embodiments, the radiotherapy apparatus further includes: a first shielding structure configured to provide magnetic shielding for the linear accelerator.

[0013] In some embodiments, the first shielding structure forms a semi-closed loop around the axis of the linear accelerator, and the semi-closed loop includes at least two plates arranged along the circumferential direction of the linear accelerator; or the radiotherapy device also includes: two annular magnetic shielding layers, and the first shielding structure is formed by at least two first magnetic shielding partitions connecting the two annular magnetic shielding layers.

[0014] In some embodiments, the annular cryostat further comprises: at least two chambers connected by a neck and in fluid communication with each other, and the annular groove is defined by at least the at least two chambers and the neck.

[0015] Some additional features of the present application may be explained in the following description. Some additional features of the present application 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. The features of the present application may be realized and achieved through practice or use of the methods, means and combinations of various aspects of the specific embodiments described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present application 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:

[0017] Figure 1 is a block diagram illustrating an exemplary radiation therapy system according to some embodiments of the present application;

[0018] Figure 2is a flow chart illustrating an exemplary process for radiation therapy in a radiation therapy system according to some embodiments of the present application;

[0019] Figure 3A An exemplary therapeutic device according to some embodiments of the present application is described;

[0020] Figure 3B Another exemplary therapeutic device according to some embodiments of the present application is described;

[0021] Figure 4A shows an upper portion of a cross-sectional view of an exemplary therapeutic device viewed along the X direction according to some embodiments of the present application;

[0022] Figure 4B shows an upper portion of a cross-sectional view of another exemplary therapeutic device viewed along the X direction according to some embodiments of the present application;

[0023] Figure 4C shows an upper portion of a cross-sectional view of another exemplary therapeutic device viewed along the X direction according to some embodiments of the present application;

[0024] Figure 4D shows an upper portion of a cross-sectional view of another exemplary therapeutic device viewed along the X direction according to some embodiments of the present application;

[0025] Figure 5A shows an upper portion of a cross-sectional view of an exemplary therapeutic device viewed along the X direction according to some embodiments of the present application;

[0026] Figure 5B shows an upper portion of a cross-sectional view of another exemplary therapeutic device viewed along the X direction according to some embodiments of the present application;

[0027] Figure 5C shows an upper portion of a cross-sectional view of another exemplary therapeutic device viewed along the X direction according to some embodiments of the present application;

[0028] Figure 5D shows an upper portion of a cross-sectional view of another exemplary therapeutic device viewed along the X direction according to some embodiments of the present application;

[0029] Fig. 6A shows an upper portion of a cross-sectional view of an exemplary therapeutic device viewed along the X direction according to some embodiments of the present application;

[0030] Figure 6B shows an upper portion of a cross-sectional view of another exemplary therapeutic device viewed along the X direction according to some embodiments of the present application;

[0031] Fig. 7Ashows an upper portion of a cross-sectional view of another exemplary therapeutic device viewed along the X direction according to some embodiments of the present application;

[0032] Figure 7B shows an upper portion of a cross-sectional view of another exemplary therapeutic device viewed along the X direction according to some embodiments of the present application;

[0033] Fig. 8A shows a perspective view of an exemplary therapeutic device according to some embodiments of the present application;

[0034] Figure 8B shows a perspective view of an exemplary therapeutic device according to some embodiments of the present application;

[0035] Fig.9A 1 shows a cryostat viewed along the axial direction according to some embodiments of the present application. Fig. 8A A cross-sectional view of the therapeutic device described in;

[0036] Fig. 9B FIG. 2 shows a perspective view of a cryostat along the axial direction (ie, the Z direction) according to some embodiments of the present application. Figure 8B A cross-sectional view of the therapeutic device described in;

[0037] Fig. 10A Some embodiments of the present application are shown Fig. 8A Another cross-sectional view of the therapeutic device described in;

[0038] Fig. 10B The diagram shows a diagram of a light source observed along the Y direction according to some embodiments of the present application. Figure 8B A cross-sectional view of the therapeutic device described in;

[0039] Fig.11A shows a cross-sectional view of an exemplary therapeutic device viewed along the X direction according to some embodiments of the present application;

[0040] Fig. 11B Another exemplary therapeutic device having two magnetic shielding structures viewed along the X direction according to some embodiments of the present application is shown;

[0041] Fig. 12A shows an upper portion of a cross-sectional view of an exemplary therapeutic device viewed along the X direction according to some embodiments of the present application;

[0042] Fig. 12B shows an upper portion of a cross-sectional view of another exemplary therapeutic device viewed along the X direction according to some embodiments of the present application;

[0043] Fig. 12Cshows an upper portion of a cross-sectional view of another exemplary therapeutic device viewed along the X direction according to some embodiments of the present application;

[0044] Fig.13A shows an upper portion of a cross-sectional view of an exemplary therapeutic device viewed along the X direction according to some embodiments of the present application;

[0045] Fig. 13B shows an upper portion of a cross-sectional view of another exemplary therapeutic device viewed along the X direction according to some embodiments of the present application;

[0046] Fig. 13C shows an upper portion of a cross-sectional view of another exemplary therapeutic device viewed along the X direction according to some embodiments of the present application;

[0047] Fig.14A shows a perspective view of an exemplary therapeutic device according to some embodiments of the present application;

[0048] Fig. 14B shows a perspective view of another exemplary therapeutic device according to some embodiments of the present application;

[0049] Fig.15A shows a perspective view of a therapeutic device according to some embodiments of the present application;

[0050] Fig. 15B shows a perspective view of a therapeutic device according to some embodiments of the present application;

[0051] Fig. 15C shows a perspective view of another therapeutic device according to some embodiments of the present application;

[0052] Fig.15D shows a perspective view of a therapeutic device according to some embodiments of the present application;

[0053] Fig.16A shows a perspective view of an exemplary therapeutic device according to some embodiments of the present application; and

[0054] Fig. 16B A perspective view of a therapeutic device according to some embodiments of the present application is shown. DETAILED DESCRIPTION

[0055] The following description is intended to enable a person of ordinary skill in the art to implement and utilize the present application, and the description is provided in the context of a specific application scenario and its requirements. It will be apparent to a person of ordinary skill in the art that various changes may be made to the disclosed embodiments, and that the general principles defined in the present application may be applied to other embodiments and application scenarios without departing from the principles and scope of the present application. Therefore, the present application is not limited to the described embodiments, but should be given the broadest scope consistent with the claims.

[0056] The terms used in this application are only used to describe specific exemplary embodiments and do not limit the scope of this application. As shown in this application and the claims, unless the context clearly indicates an exception, the words "one", "a", "a kind" and / or "the" do not specifically refer to the singular and may also include the plural. It should be understood that the terms "including" and "comprising" used in this application only indicate the features, integers, steps, operations, elements and / or parts that have been clearly identified, and do not exclude the presence and addition of one or more other features, integers, steps, operations, elements, parts and / or combinations thereof.

[0057] These and other features, characteristics and functions and methods of operation of the related structural elements of the present application, as well as the combination of components and manufacturing economy, may become more apparent from the following description of the accompanying drawings, which form a part of the specification of this application. 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 application. It should be understood that the drawings are not drawn to scale.

[0058] Figure 1 1 is a block diagram showing an exemplary radiation therapy system 100 according to some embodiments of the present application. In some embodiments, the radiation therapy system 100 may be a multi-modality imaging system, including, 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 application, the MRI-RT system may be described as an example of the radiation therapy system 100, and is not intended to limit the scope of the present application.

[0059] like Figure 1 As shown, the radiation therapy system 100 may include a treatment device 110, one or more processing engines 120, a network 130, a storage device 140, and one or more terminal devices 150. In some embodiments, the treatment device 110, the one or more processing engines 120, the storage device 140, and / or the terminal device 150 may be connected and / or communicate with each other via a wireless connection (e.g., a wireless connection provided by the network 130), a wired connection (e.g., a wired connection provided by the network 130), or any combination thereof.

[0060] The treatment device 110 may include a magnetic resonance imaging device (hereinafter referred to as an "MRI device"). The MRI device may generate image data related to a magnetic resonance imaging signal (hereinafter referred to as an "MRI signal") by scanning a subject or a portion of the subject. In some embodiments, the subject may include a body, a substance, an object, etc., or any combination thereof. In some embodiments, the subject may include a specific part of the body, a specific organ, or a specific tissue, such as the head, brain, neck, body, shoulder, arm, chest, heart, stomach, blood vessel, soft tissue, knee, foot, etc., or any combination thereof. In some embodiments, the treatment device 110 may send the image data to one or more processing engines 120, a storage device 140, and / or a terminal device 150 via a network 130 for further processing. For example, the image data may be sent to one or more processing engines 120 to generate an MRI image, or may be stored in a storage device 140.

[0061] The treatment device 110 may also include a radiotherapy component (hereinafter referred to as a "radiotherapy device"). The radiotherapy device can provide radiotherapy for a target area (e.g., a tumor). The radiation used here may include particle rays, photon rays, and the like. Particle rays may include neutrons, protons, electrons, muons, heavy ions, alpha rays, and the like, or any combination thereof. Photon rays may include X-rays, gamma rays, ultraviolet rays, lasers, and the like, 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 with the help of image data provided by an MRI device to perform radiotherapy. For example, the image data may be processed to locate a tumor and / or determine the dose of the X-rays.

[0062] One or more processing engines 120 can process data and / or information obtained from the treatment device 110, the storage device 140 and / or the terminal device 150. For example, one or more processing engines 120 can process image data and reconstruct at least one MRI image based on the image data. And, one or more processing engines 120 can determine the position and radiation dose of the treatment area based on at least one MRI image. The benefits that MRI images can provide include, for example, excellent soft tissue contrast, high resolution, geometric accuracy, which can allow accurate positioning of the treatment area. MRI images can be used to detect changes in the treatment area (e.g., tumor regression or metastasis) during the determination of the treatment plan and the time of performing the treatment, so that the original treatment plan can be adjusted accordingly. The original treatment plan can be determined before the treatment begins. For example, the original treatment plan can be determined at least one day, or three days, or one week, or two weeks, or one month before the treatment begins.

[0063] In the original or adjusted treatment plan, the radiation dose may be determined based on, for example, the synthesized electron density information. In some embodiments, the synthesized electron density information may be generated based on MRI images.

[0064] In some embodiments, the one or more processing engines 120 may be a single processing engine that communicates with the MRI device and the radiotherapy device of the treatment device 110 and processes data. Alternatively, the one or more processing engines 120 may include at least two processing engines. One of the at least two processing engines may communicate with the MRI device of the treatment device 110 and process data, and another of the at least two processing engines may communicate with the radiotherapy device of the treatment device 110 and process data. In some embodiments, the one or more processing engines 120 may include a treatment planning system. The at least two processing engines may communicate with each other.

[0065] In some embodiments, one or more processing engines 120 may be a single server or a server group. The server group may be centralized or distributed. In some embodiments, one or more processing engines 120 may be located at a local or remote treatment device 110 of the treatment device 110. For example, one or more processing engines 120 may access information and / or data from the treatment device 110, storage device 140, and / or terminal device 150 via network 130. For example, one or more processing engines 120 may be directly connected to the treatment device 110, terminal device 150, and / or storage device 140 to access information and / or data. In some embodiments, one or more processing engines 120 may 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.

[0066] 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, one or more processing engines 120, the storage device 140, or the terminal device 150) can communicate with one or more other components of the radiation therapy system 100 via the network 130 to obtain information and / or data. For example, the one or more processing engines 120 can obtain image data from the treatment device 110 via the network 130. For another example, the one or more processing engines 120 can 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., an Ethernet network), 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, etc., 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.

[0067] 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 one or more processing engines 120 and / or terminal devices 150. In some embodiments, the storage device 140 may store data and / or instructions that one or more processing engines 120 may execute or be used to execute the exemplary methods described in this application. 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 devices may include magnetic disks, optical disks, solid-state disks, etc. Exemplary removable storage devices may include flash drives, floppy disks, optical disks, memory cards, compressed disks, tapes, etc. Exemplary volatile read-write storage devices may include random access memory (RAM). Exemplary RAM may include dynamic random access memory (DRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), static random access memory (SRAM), thyristor random access memory (T-RAM), and zero capacitance random access memory (Z-RAM), etc. Exemplary read-only storage devices 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 disk read-only memory (CD-ROM), and digital versatile disk read-only memory, etc. In some embodiments, storage device 140 may be implemented on a cloud platform as described elsewhere in this application.

[0068] In some embodiments, storage device 140 may be connected to network 130 to communicate with one or more other components of radiation therapy system 100 (e.g., one or more processing engines 120 or terminal device 150). One or more components of radiation therapy system 100 may access data or instructions stored in storage device 140 via network 130. In some embodiments, storage device 140 may be part of one or more processing engines 120.

[0069] The terminal device 150 can be connected to the treatment device 110, one or more processing engines 120 and / or storage device 140, and / or communicate with the treatment device 110. For example, one or more processing engines 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 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. For example, 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, a laptop computer, a tablet computer, a desktop computer, 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 alphanumeric and other keys that can be input through a keyboard, a touch screen (e.g., with tactile or haptic feedback), voice input, eye tracking input, a brain monitoring system, or any other similar input mechanism. The input information received by the input device can be sent to one or more processing engines 120 via, for example, a bus, for further processing. Other types of input devices can include cursor control devices, such as a mouse, a trackball, or cursor direction keys. Output devices can include displays, speakers, printers, etc., or any combination thereof. In some embodiments, terminal device 150 can be a part of one or more processing engines 120.

[0070] This description is intended to illustrate, rather than limit the scope of the present application. Many substitutions, modifications, and variations are apparent to those of ordinary skill in the art. The features, structures, methods, and characteristics 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 including a cloud computing platform, such as a public cloud, a private cloud, a community, a hybrid cloud, etc. In some embodiments, one or more processing engines 120 may be integrated into the treatment device 110. However, those variations and modifications will not depart from the scope of the present application.

[0071] Figure 2 is a flow chart of an exemplary process 200 for applying radiation therapy by a radiation therapy system according to some embodiments of the present application. In some embodiments, Figure 2 One or more operations of process 200 shown in FIG. Figure 1 The invention is implemented in the radiation therapy system 100 shown in FIG. For example, Figure 2 The process 200 shown in FIG. 1 may be stored in the form of instructions in the storage device 140 and executed by Figure 1The one or more processing engines 120 shown in are called and / or executed. For illustrative purposes, the implementation of the process 200 in one or more processing engines 120 is described herein as an example. It should be noted that the process 200 can also be similarly implemented in the terminal device 150.

[0072] In 202, one or more processing engines 120 may acquire magnetic resonance imaging (MRI) data about a region of interest (ROI) through an MRI device. The MRI data may be MR signals received by an RF coil from a subject. A more detailed description of MR signals may be found elsewhere in this application, for example, FIG. 3 and its description.

[0073] In some embodiments, the ROI may refer to a treatment region associated with a tumor. The treatment region may be a region of a subject (e.g., body, substance, object). In some embodiments, the ROI may be a specific part of the body, a specific organ, or a specific tissue, such as the head, brain, neck, body, shoulder, arm, chest, heart, stomach, blood vessel, soft tissue, knee, foot, etc., or any combination thereof.

[0074] In 204, one or more processing engines 120 may reconstruct an MRI image associated with at least a portion of the ROI based on the MRI data. The MRI image may be reconstructed as a distribution of nuclei within the object based on the MRI data. Different types of image reconstruction techniques may be employed for the image reconstruction process. Exemplary image reconstruction techniques may include Fourier reconstruction, constrained image reconstruction, and regularized image reconstruction in MRI, etc., or variations thereof, or any combination thereof.

[0075] MRI images can be used to determine radiation therapy for tumors. For example, one or more processing engines 120 can determine the location and radiation dose of the tumor based on the MRI image. In some embodiments, it may take at least several minutes to reconstruct an MRI image representing a large imaging area. In some embodiments, in order to generate an MRI image during a relatively short period of time (e.g., every second), one or more processing engines 120 can reconstruct an initial image representing a smaller imaging area (e.g., at least a portion of the ROI) compared to an MRI image representing a large imaging area, and then combine the initial image with the MRI image representing the large imaging area. For example, one or more processing engines 120 can replace a portion of the MRI image representing a large imaging area associated with the ROI with the initial image. The MRI image representing the large imaging area may include information of non-ROIs (e.g., healthy tissues) and ROIs near the ROI. In some embodiments, an MRI image representing a large imaging area can be acquired and reconstructed before radiation therapy on a tumor. For example, an MRI image representing a large imaging region may be acquired in less than 1 day, or half a day, or 6 hours, or 3 hours, or 1 hour, or 45 minutes, or 30 minutes, or 20 minutes, or 15 minutes, or 10 minutes, or 5 minutes, etc., before the radiation source begins emitting radiation beams for treatment. In some embodiments, an MRI image representing a large imaging region may be acquired from a storage device in the radiation therapy system 100, such as the storage device 140.

[0076] In 206, one or more processing engines 120 may determine parameters associated with the size of at least a portion of the ROI based on the MRI image. In some embodiments, the parameters associated with the size of at least a portion of the ROI may include the size of a cross section of the tumor, which has a maximum area and is perpendicular to the direction of the radiation beam irradiating the tumor. In some embodiments, the parameters 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 parameters 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 circular and also indicate the diameter of the circle. In some embodiments, in order to determine the parameters associated with the size of at least a portion of the ROI, one or more processing engines 120 may extract texture information from the MRI image and determine the texture features indicating the ROI in the extracted texture information by identifying the texture features. Then, the one or more processing engines 120 may measure the size of the area including the texture features in the MRI image and determine the parameters associated with the size of the ROI.

[0077] In 208, one or more processing engines 120 may generate a control signal based on a parameter associated with the size of at least a portion of the ROI. The control signal may be dynamically adjusted based on at least two MRI images taken at different time points. In some embodiments, the control signal may include parameters related to radiation therapy on the tumor. For example, the control signal may include a dose of X-rays and a duration of the radiation beam. For another example, the control signal may include parameters of a multi-leaf collimator (MLC) that determines the shape of the radiation beam projected on the object. The MLC may include at least two separate high atomic number material (e.g., tungsten) leaves that independently move in and out of the path of the radiation beam. In some embodiments, the control signal may include 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 (e.g., a radiotherapy device in the treatment device 110, a radiotherapy device 300). As another example, the control signal may include parameters associated with the height or position of the platform of the radiotherapy device (e.g., the position of the platform 308 of the treatment couch 330 along the axis of the magnet 302) to appropriately position the patient so that a treatment area in the patient (e.g., a cancerous tumor or lesion) can appropriately receive a radiation beam from the radiotherapy device.

[0078] In 210, one or more processing engines 120 may send a control signal to the radiotherapy device to cause the radiotherapy device to apply radiotherapy. During radiotherapy, the radiation source of the radiotherapy device may rotate, and the dose of X-rays, the duration of the radiation beam from the radiation source, the shape of the MLC, and the position of the platform may be changed. In some embodiments, the radiation beam may be emitted only when the radiation source of the radiotherapy device is rotated to certain angles (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 there, and 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.

[0079] In some embodiments, as described above, a treatment area (e.g., an area including a tumor) can be determined based on image data acquired from an MRI device. Then, a radiation beam can be generated by a radiation source of a radiotherapy device to perform radiation therapy of the treatment area. For example, the dose of the radiation beam and / or the location of the treatment area can be determined in real time with the help of an MRI device.

[0080] It should be noted that the above is provided for illustrative purposes only and is not intended to limit the scope of the present application. For those of ordinary skill in the art, various changes and modifications can be made according to the description of the present application. However, these changes and modifications will not deviate from the scope of the present application. For example, operations 202 and 204 can be performed simultaneously.

[0081] Figure 3A An exemplary treatment device 110 according to some embodiments of the present application is illustrated. Figure 3A As shown, the treatment device 110 may include an MRI device 310, a radiation therapy device 300, and a treatment couch 330. In some embodiments, the MRI device 310 may generate MRI data as described in operation 202, and the radiation therapy device 300 may perform radiation therapy as described in operation 210.

[0082] MRI device 310 may include bore 301, magnet 302, one or more gradient coils (not shown), and one or more radio frequency (RF) coils (not shown). MRI device 310 may be configured to acquire image data from an imaging region. For example, the image data may relate to a treatment region associated with a tumor. In some embodiments, depending on the type of magnet 302, MRI device 310 may be a permanent magnet MRI scanner, a superconducting electromagnetic MRI scanner, or a resistive electromagnetic MRI scanner, etc. In some embodiments, depending on the strength of the magnetic field, MRI device 310 may be a high field MRI scanner, a mid-field MRI scanner, a low field MRI scanner, etc. In some embodiments, MRI device 310 may be a closed-hole (cylindrical) type, an open-hole type, etc.

[0083] The magnet 302 may have a ring shape and may generate a static magnetic field B0. The magnet 302 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.

[0084] One or more gradient coils can generate magnetic field gradients 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, etc. For example, the Z-direction coil can be designed based on a circular (Maxwell) coil, and the X-direction coil and the Y-direction coil can be designed based on a saddle (Golay) coil. 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 slice selection encoding direction. In the present application, the readout direction and the frequency encoding direction may be used interchangeably.

[0085] 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, and a readout (RO) gradient field corresponding to the X direction, etc. Gradient magnetic fields in different directions can be used to encode the spatial information of the MR signal. In some embodiments, the gradient magnetic field can also be used to perform at least one function of flow encoding, flow compensation, flow dephasing, etc., or any combination thereof.

[0086] One or more RF coils can transmit RF pulses to the object (e.g., body, substance, object) being examined and / or receive MR signals therefrom. As used herein, RF pulses can include excitation RF pulses and refocusing RF pulses. In some embodiments, an excitation RF pulse (e.g., a 90-degree RF pulse) can cause the magnetization vector to move away from the direction of the main magnetic field B0. In some embodiments, a refocusing pulse (e.g., a 180-degree RF pulse) can rotate the rotation of the scattered spins around an axis in the transverse plane so that the magnetization vector can be re-phased at a later time. In some embodiments, the RF coil may include an RF transmitting coil and an RF receiving coil. The RF transmitting coil may transmit an RF pulse signal that can excite the nuclei in the subject to resonate at the Larmor frequency. The RF receiving coil may receive MR signals emitted from the object. In some embodiments, the RF transmitting coil and the RF receiving coil may be integrated into a single coil, such as a transmitting / receiving coil. The RF coil may be one of various types, including, for example, a quotient difference (QD) orthogonal coil, a phase array coil, and the like. In some embodiments, different RF coils 240 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 coils may be classified into volume coils and local coils according to their functions and / or sizes. 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.

[0087] The radiotherapy device 300 may include a drum 312 and a base 307. The drum 312 may have a ring shape. The drum 312 may be arranged around the magnet 302 and intersect the magnet 302 along the axis 311 of the hole 301 at the central area of ​​the magnet 302. The drum 312 may accommodate and support a radiation source configured to emit a radiation beam toward a treatment area in the hole 301. The radiation beam may be an X-ray beam, an electron beam, a gamma ray source, a proton ray source, etc. The drum 312, together with the radiation source mounted thereon, is capable of rotating around the axis 311 of the hole 301 and / or a point called the isocenter. By way of example only, the drum 312, together with the radiation source mounted thereon, may rotate around the axis 311 at any angle, such as 90 degrees, 180 degrees, 360 degrees, 450 degrees, 540 degrees. The drum 312 may be further supported by the base 307.

[0088] It should be noted that the above is provided for illustrative purposes only and is not intended to limit the scope of the present application. For those with ordinary skills in the art, various changes or modifications can be made under the teachings of the present application. For example, the radiotherapy device 300 may also include a linear accelerator for accelerating electrons, ions or protons, a dose detection device, a temperature control device (e.g., a cooling device), a multilayer collimator, etc., or any combination thereof. However, these changes and modifications will not deviate from the scope of the present application.

[0089] The treatment couch 330 may include a platform 308 and a base 309. In some embodiments, the platform 308 may move in a horizontal direction and enter the bore 301 of the MRI device 310. In some embodiments, the platform 308 may move in two, three, four, five, or six dimensions. In some embodiments, the platform 308 may move according to changes (e.g., position changes) of a tumor estimated by, for example, real-time MRI images acquired during treatment.

[0090] In some embodiments, the subject can be placed on the platform 308 and sent to the MRI device. In some embodiments, the subject can be a human patient. The human patient can lie on his back, prone, or on the side of the platform 308.

[0091] During processing, the roller 312 can be set to rotate around the magnet 302. In some embodiments, the magnet 302 may include a groove (not shown) at its outer wall. The groove can be arranged around the entire circumference of the magnet 302. For example, the groove can have an annular shape around the magnet 302, thereby accommodating at least a portion of the roller 312. In some embodiments, the groove can be arranged around a portion of the circumference of the magnet 302. For example, the groove can have a shape of one or more arcs around the magnet 302.

[0092] In some embodiments, the radiation source may move along the entire rotation path within the groove. The radiation source may generate a radiation beam according to one or more parameters. Exemplary parameters may include parameters of the radiation beam, parameters of the radiation source, or parameters of the platform 308. For example, 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 position, rotation angle, rotation speed, rotation direction, configuration of the radiation source, etc., or any combination thereof. In some embodiments, the radiation source may generate a radiation beam taking into account energy loss of the radiation beam, because, for example, a magnet 302 located in the path of the radiation beam may absorb at least a portion of the radiation beam. For example, the irradiation intensity of the radiation beam may be set to be greater than a case where there is no energy loss, because, for example, the absorption of the magnet 302 thus compensates for the energy loss, so that the radiation beam-specific intensity of the radiation beam may affect the treatment area (e.g., a tumor).

[0093] Figure 3B Another exemplary treatment device 110′ according to some embodiments of the present application is illustrated. Figure 3A Compared to the treatment device 110 described in the embodiment of the present invention, the treatment device 110' may use a gantry 306 instead of a roller 312. The gantry 306 may be disposed on one side of the magnet 302. The treatment head 304 may be mounted on the gantry 306 via a treatment arm 305. The treatment head 304 may accommodate a radiation source. The gantry 306 may be capable of rotating the treatment head 304 around the axis 311 of the hole 301.

[0094] like Figure 3B As shown, the groove 303 may be formed on the outer wall of the magnet 302 and have an annular shape. The groove 303 may accommodate at least a portion of the treatment head 304 and provide a path for the rotation of the treatment head 304. This arrangement may reduce the distance between the treatment head 304 and the axis 311 of the hole 301 along the radial direction of the magnet 302. In some embodiments, the reduction in the distance between the treatment head 304 and the axis 311 of the hole 301 may cause an increase in the radiation dose that can reach the treatment area (e.g., a tumor), which leads to an improvement in treatment efficiency. In some embodiments, the width of the groove 303 along the Z direction (i.e., the axial direction of the magnet 302) may not be less than the width of the treatment head 304 along the Z direction.

[0095] It should be noted that the description of the above-mentioned treatment device 110 is provided for illustrative purposes only and is not intended to limit the scope of the present application. For those of ordinary skill in the art, various changes and modifications can be made according to the description of the present application. For example, the assembly and / or function of the treatment device 110 can be changed or altered according to the specific embodiment. In some embodiments, the magnet 302 of the MRI device 310 can also rotate relative to the treatment head 304. For example, the radiotherapy device 300 and the MRI device 310 can rotate synchronously or asynchronously around the same axis (e.g., axis 311). However, these changes and modifications will not deviate from the scope of the present application.

[0096] Figure 4A An upper portion of a cross-sectional view of an exemplary treatment apparatus 400 viewed along the X direction according to some embodiments of the present application is shown. Treatment apparatus 400 may include an MRI apparatus configured to generate MRI data and a radiation therapy apparatus configured to apply radiation therapy.

[0097] like Figure 4A As shown, the MRI apparatus may include at least two main magnetic coils 401 , at least two magnetic shielding coils 402 , and a cryostat 403 .

[0098] At least two main magnetic coils 401 and at least two magnetic shield coils 402 may be housed in a cryostat 403 and maintained in a superconducting state under certain conditions (eg, when the two coils are immersed in a cooling medium in the cryostat 403 ).

[0099] Cryostat 403 may have the shape of a ring with shaft 405 (eg, Figure 3A When the at least two main magnetic coils 401 transmit current along the first direction, the at least two main magnetic coils 401 may be coaxially arranged along the axis 405 to generate a uniform magnetic field (e.g., a main magnetic field B0) in a specific area (e.g., an area within the hole 301).

[0100] The at least two magnetic shielding coils 402 may also be coaxially arranged along the axis 405 at a greater radius from the axis 405 than the at least two main magnetic coils 401. The at least two magnetic shielding coils 402 may transmit current in a second direction opposite to the first direction. The at least two magnetic shielding coils 402 may help shield the magnetic field generated by the at least two main magnetic coils 401 from an area outside the MRI device.

[0101] like Figure 4AAs shown, the cryostat 403 may include two chambers (e.g., a left chamber and a right chamber for simplicity). The two chambers may be located on opposite sides of the cryostat 403 in the axial direction (i.e., the direction of the axis 405) and may be connected by a neck between the two chambers. The radial dimension of the neck may be smaller than the two chambers. Each chamber may have a ring shape with different outer walls. In some embodiments, the outer wall may refer to the outermost surface of each chamber having a ring shape. The two chambers and the neck may share the same inner wall, i.e., the inner wall of the cryostat 403. In some embodiments, the inner wall may refer to the innermost surface of each chamber, which also has a ring shape. In some embodiments, each chamber may accommodate at least one coil of at least two main magnetic coils 401 and at least one coil of at least two magnetic shielding coils 402. For example, at least one coil of at least two main magnetic coils 401 may be arranged near the inner wall of the left chamber, and at least one coil of at least two magnetic shielding coils 402 may be arranged near the outer wall of the left chamber. A gap 406 may be formed between the main magnetic coil disposed in the left chamber and the main magnetic coil disposed in the right chamber, allowing a radiation beam generated by the radiotherapy device to pass through. The two chambers may be fluidically connected to each other through a neck therebetween. The cryostat 403 may contain a cooling medium in which at least two main magnetic coils 401 and at least two magnetic shielding coils 402 are immersed to achieve a superconducting state.

[0102] The cryostat 403 may have a groove 408 at a radial position between the inner wall of the cryostat 403 and the outer walls of different chambers of the cryostat 403. The groove 408 may have an opening 407 formed between the outer walls of the two chambers of the cryostat 403. When viewed in a perspective view, the groove 408 may have a ring shape. The ring may have the same or different widths (i.e., the size in the axial direction) at different radial positions. The groove 408 may have a depth (i.e., the thickness of the ring in the radial direction), which is defined as the distance from the opening 407 of the cryostat 403 to the outermost surface of the neck in the radial direction.

[0103] Recess 408 may be configured to accommodate components of a radiotherapy device. Figure 4A As shown, the recess 408 may accommodate a radiation source, which includes a linear accelerator 409 , a shielding structure 411 , a collimator 412 , a target 404 , and a multi-leaf collimator (MLC) 410 .

[0104] The linear accelerator 409 can be configured to accelerate charged subatomic particles or ions to high speeds. In some embodiments, the linear accelerator 409 can accelerate electrons using microwave technology. For example, the linear accelerator 409 can use high RF electromagnetic waves to accelerate electrons in an electron beam having an energy group between 4 MeV and 22 MeV.

[0105] The linear accelerator 409 may be mounted to a gantry or drum (e.g., gantry 306 or drum 312) that is capable of rotating about axis 405 and enabling the radiation beam to be emitted from any circumferential position. Figure 4A As shown, the gantry or drum can be rotated to a first position and the linear accelerator 409 can be located above the axis 405. The linear accelerator 409 can include an accelerating waveguide (tube) whose axis is perpendicular to the axis 405. The accelerating waveguide (tube) can provide a linear path for accelerating electrons along a beam path perpendicular to the axis 405.

[0106] The accelerating waveguide (tube) of the linear accelerator 409 can be at least partially surrounded by a shielding structure 411. In some embodiments, the shielding structure 411 can provide a cavity coaxial with the longitudinal axis of the tube of the linear accelerator 409, wherein at least one end is open to allow a radiation beam emitted from the linear accelerator 409 to pass through. In some embodiments, the shielding structure 411 can have any configuration. For example, the shielding structure 411 can include an annular space on the left side of the groove (i.e., the side near the left chamber) and an annular plate on the right side of the groove (i.e., the side near the right chamber), with a plate connecting the two rings. Alternatively, the ring can be replaced by a separate arc segment. It should be noted that the shielding structure 411 can be of any shape, as long as at least one end of the shielding structure 411 is open to allow the radiation beam emitted from the linear accelerator 409 to pass through. Details on exemplary configurations of the shielding structure 411 can be found elsewhere in this application (e.g., Figure 8A-16B and its description).

[0107] In some embodiments, the shielding structure 411 may include at least two shielding layers. At least one of the at least two shielding layers may be used to reduce magnetic interference between one or more components of the MRI device and the radiotherapy device. For example, the shielding structure 411 may include a magnetic shielding layer configured to shield the magnetic field (e.g., main magnetic coil, magnetic shielding coil, gradient coil) generated by the MRI device to prevent the electrons from being affected by the magnetic field.

[0108] In addition, at least one of the at least two shielding layers can be used to reduce RF and / or microwave interference between one or more components of the MRI device and the radiotherapy device. For example, the shielding structure 411 can include an electromagnetic shielding layer configured to shield RF signals generated by the MRI device (e.g., an RF coil) and microwaves generated by the radiotherapy device.

[0109] At least two shielding layers can be made of the same material and / or different materials. For example, both the electromagnetic shielding layer and the magnetic shielding layer can be made of high magnetic susceptibility and magnetic permeability materials (e.g., non-oriented silicon steel), or one of the electromagnetic shielding layer and the magnetic shielding layer can be made of high electrical conductivity and magnetic permeability materials. In some embodiments, at least two shielding layers can be magnetically and / or electrically isolated from each other with a suitable dielectric material (e.g., air or plastic) between them.

[0110] Additionally or alternatively, at least one of the at least two shielding layers can be used to protect one or more components of the MRI device from radiation generated by the linear accelerator 409. For example, one of the at least two shielding layers can be made of a material capable of absorbing radiation generated by the radiation beam of the linear accelerator 409. Exemplary materials capable of absorbing radiation may include materials for absorbing photon rays and / or materials for absorbing neutron rays. Materials that absorb photon rays may include steel, aluminum, lead, tungsten, etc. Materials that absorb neutron rays may include boron, graphite, etc. It should be noted that in some embodiments, the shielding structure 411 may be made only of radiation absorbing materials without high magnetic susceptibility and permeability materials. In this way, the shielding structure 411 can provide radiation shielding only for one or more components of the MRI device.

[0111] Target 404 can be configured to receive accelerated charged subatomic particles or ions (e.g., electron beams) to produce radiation beams for radiotherapy. For example, based on the bremsstrahlung effect, the electron beam can collide with target 404 to produce high-energy X-rays. In some embodiments, target 404 can be located near the exit window of linear accelerator 409 to receive the accelerated electron beam. In some embodiments, target 404 can be made of a material including aluminum, copper, silver, tungsten, etc., or any combination thereof. Alternatively, target 404 can be made of a composite material including tungsten and copper, tungsten and silver, tungsten and aluminum, etc., or any combination thereof.

[0112] The radiation beam from target 404 may pass through collimator 412 to form a beam having a particular shape (eg, a cone beam). In some embodiments, collimator 412 may include a primary collimator, a flattener, and at least one secondary collimator.

[0113] The MLC 410 can be configured to reshape the radiation beam. For example, the MLC 410 can adjust the radiation beam's irradiation shape, irradiation area, etc. The MLC 410 can be placed anywhere along the radiation beam's path. For example, the MLC 410 can be placed near the linear accelerator 409, such as Figure 4AThus, after being reshaped by the MLC 410, the radiation beam can further pass through the neck of the cryostat 403 and the gap 406 between at least two main magnetic coils to reach the treatment area. For example, the MLC 410 can be placed at a relatively long distance from the linear accelerator (e.g., Fig. 6A ), so that the MLC 410 can be closer to, for example, a patient to be irradiated.

[0114] The MLC 410 can be held stationary relative to the linear accelerator 409 so as to rotate with the linear accelerator 409 about the axis 405. The MLC 410 can include at least two separate blades of a high atomic number material (e.g., tungsten) that independently move in and out of the path of the radiation beam to block it. As the at least two separate blades move in and out, the shape of the radiation beam can change, forming different slots that simulate a rotation from the axis of the radiation beam (i.e., Figure 4A 416). In some embodiments, MLC 410 may include one or more leaf layers. For example, MLC 410 may have only one layer of leaves, and the height of MLC 410 along the axis of the radiation beam may be between 7 and 10 centimeters. For another example, MLC 410 may include two layers, and the height of MLC 410 may be at least 15 centimeters.

[0115] Figure 4B FIG. 4 shows an upper portion of a cross-sectional view of an exemplary treatment device 400 ′ viewed along the X direction according to some embodiments of the present application. Figure 4A Compared to the treatment device 400 described in the foregoing, at least a portion of the linear accelerator 409 of the treatment device 400' may be located outside the groove 408 along the radial direction of the cryostat 403. Figure 4B As shown, the linear accelerator 409 and the shielding structure 411 surrounding it along the axis of the radiation beam can extend out of the opening 407 formed by the outer wall of the cryostat 403. In some embodiments, the linear accelerator 409 and the shielding structure 411 can be supported by or mounted to a frame or roller (e.g., frame 306 or roller 312) that can rotate about the axis 405.

[0116] Figure 4C 4 shows an upper portion of a cross-sectional view of an exemplary treatment device 400" viewed along the X direction according to some embodiments of the present application. Figure 4A Compared to the treatment device 400 described in the above, the cryostat 403' of the treatment device 400" may have two independent chambers. Figure 4CAs shown, the left chamber 403a and the right chamber 403b may be independent of each other, so no fluid communication is established between them. The cryostat 403' may have two different inner walls for the left chamber 403a and the right chamber 403b. Another opening 413 of the groove 408 may be formed between the two different inner walls. After being reshaped by the MLC 410, the radiation beam may pass through the opening 413 and reach the processing area.

[0117] Figure 4D 4 shows an upper portion of a cross-sectional view of another exemplary treatment device 400'' viewed along the X direction according to some embodiments of the present application. Figure 4C Compared to the treatment device 400" described in the foregoing, at least a portion of the linear accelerator 409 of the treatment device 400"' may be located outside the groove 408 in the radial direction of the cryostat 403'. Figure 4D As shown, the linear accelerator 409 and the shielding structure 411 surrounding it along the axis of the radiation beam can extend out of the opening 407 formed by the outer wall of the cryostat 403'. In some embodiments, the linear accelerator 409 and the shielding structure 411 can be supported by or mounted to a frame or roller (e.g., frame 306 or roller 312) that can rotate about axis 405.

[0118] It should be noted that the description of the above-mentioned treatment devices 400, 400', 400" or 400'" is provided for illustrative purposes only and is not intended to limit the scope of the present application. For those of ordinary skill in the art, various changes and modifications can be made based on the description of the present application. For example, the collimator 412 and the MLC 410 can be integrated to form a single collimator. For another example, the neck shown in the cryostat 403 may not form a complete ring. Specifically, the neck can be a discrete arc connecting the left chamber and the right chamber of the cryostat 403. Therefore, when the linear accelerator 409 rotates about the axis 405, the neck can intermittently appear in the path of the radiation beam to generate the radiation beam.

[0119] Figure 5A FIG. 5 shows an upper portion of a cross-sectional view of an exemplary treatment device 500 viewed along the X direction according to some embodiments of the present application. Figure 5AAs shown, the treatment device 500 may include at least two main magnetic coils 501, at least two magnetic shielding coils 502, a cryostat 503 having an axis, a target 504, a gap 506, an opening 507, a groove 508, a linear accelerator 509, an MLC 510, a shielding structure 511, a collimator 512, and a deflection unit 513. The at least two main magnetic coils 501, the at least two magnetic shielding coils 502, the cryostat 503, the target 504, the axis 505, the gap 506, the opening 507, the groove 508, the MLC 510, and the collimator 512 may be similar to the at least two main magnetic coils 401, the at least two magnetic shielding coils 402, the cryostat 403, the target 404, the axis 405, the gap 406, the opening 407, the groove 408, the MLC 410, and the collimator 412, and their descriptions are not repeated here.

[0120] Unlike the linear accelerator 409, the axis of the acceleration waveguide (tube) of the linear accelerator 509 can be parallel to the axis 505. Therefore, the acceleration waveguide (tube) can provide a linear path for accelerating electrons along a beam path parallel to the axis 505 (also referred to as "parallel beam passing"). At least two main magnetic coils 501 and at least two magnetic shielding coils 502 can generate a magnetic field parallel or substantially parallel to the axis 505 (also referred to as a "parallel magnetic field"). It should be understood that the parallel magnetic field can have a minimal effect on the parallel beam channel. Therefore, the linear accelerator 509 can help reduce the effect of the magnetic field generated by the MRI device on the electrons. Similarly, the acceleration waveguide (tube) of the linear accelerator 509 can be at least partially surrounded by a shielding structure 511. The shielding structure 511 can be continuously distributed in the direction of the axis 505. In some embodiments, the shielding structure 511 can extend along the axial direction to cover both ends of the linear accelerator, which means that the shielding structure 511 can have a larger size than the linear accelerator 509 along the axial direction. The shielding structure 511 can be configured to further reduce interference from the magnetic field generated by the MRI device.

[0121] The deflection unit 513 may be configured to deflect the accelerated electrons from the parallel beam path onto the target 504. In some embodiments, the deflected electrons may impact the target 504 vertically, so the deflection angle of the electrons may be 90 degrees or 270 degrees. In some embodiments, the deflection unit 513 may include one or more magnets configured to provide a deflection magnetic field to deflect the accelerated electrons.

[0122] like Figure 5AAs shown, the linear accelerator 509 and the deflection unit 513 are both disposed in the groove 508 between the opening 507 and the gap 506. In some embodiments, the magnetic shielding coils are not disposed to "cover" the linear accelerator 509 and / or the deflection unit 513 in the radial direction of the cryostat 503. That is, there is no overlap between the axial positions of the at least two magnetic shielding coils 502 and the axial positions of the linear accelerator 509 and / or the deflection unit 513. In addition, the cryostat 503 may have a continuous body (i.e., a body providing continuous fluid communication) in the radial direction of the cryostat 503, which accommodates at least two main magnetic coils 501 and at least two magnetic shielding coils 502.

[0123] Figure 5B FIG. 5 shows an upper portion of a cross-sectional view of an exemplary treatment device 500 ′ viewed along the X direction according to some embodiments of the present application. Figure 5A Compared to the treatment device 500 described in the foregoing, at least a portion of the linear accelerator 509 of the treatment device 500' may be located outside the groove 508 along the radial direction of the cryostat 503. Figure 5B As shown, the linear accelerator 509, the shield structure 511, and the deflection unit 513 can at least partially extend out of the opening 507 formed by the outer wall of the cryostat 503. In some embodiments, the linear accelerator 509 and the shield structure 511 can be supported by or mounted to a frame or roller (e.g., the frame 306 or the roller 312) that can rotate about the axis 505.

[0124] Figure 5C 2 shows an upper portion of a cross-sectional view of another exemplary treatment device 500" viewed along the X direction according to some embodiments of the present application. Figure 5A Compared to the treatment device 500 described in the above, the cryostat 503' of the treatment device 500" may have two independent chambers. Figure 5C As shown, the left chamber 503a and the right chamber 503b may be independent of each other, so no fluid communication is established between them. The cryostat 503' may have two different inner walls for the left chamber 503a and the right chamber 503b. Another opening 513 of the groove 508 may be formed between the two different inner walls. After being reshaped by the MLC 510, the radiation beam may pass through the opening 513 and reach the processing area.

[0125] Figure 5D 5 shows an upper portion of a cross-sectional view of an exemplary treatment device 500'' viewed along the X direction according to some embodiments of the present application. Figure 5C Compared to the treatment device 500" described in the embodiment of the present invention, at least a portion of the linear accelerator 509 of the treatment device 500"' may be located outside the groove 508 in the radial direction of the cryostat 503'. Figure 5D As shown, the linear accelerator 509, the shielding structure 511, and the deflection unit 513 can at least partially extend out of the opening 507 formed by the outer wall of the cryostat 503'. In some embodiments, the linear accelerator 509, the shielding structure 511, and the deflection unit 513 can be supported by or mounted to a frame or roller (e.g., the frame 306 or the roller 312) and can rotate around the axis 505.

[0126] It should be noted that the description of the above-mentioned treatment device 500, 500', 500" or 500'" is provided for illustrative purposes only and is not intended to limit the scope of the present application. For a person skilled in the art, various changes and modifications can be made based on the description of the present application. For example, the collimator 512 and the MLC 510 can be integrated to form a single collimator. For another example, the neck shown in the cryostat 503 may not form a complete ring. Specifically, the neck can be a discrete arc connecting the left chamber and the right chamber of the cryostat 503. Therefore, when the linear accelerator 509 rotates about the axis 505, the neck can intermittently appear in the path of the radiation beam to generate the radiation beam.

[0127] Fig. 6A FIG. 6 shows an upper portion of a cross-sectional view of an exemplary treatment device 600 viewed along the X direction according to some embodiments of the present application. Fig. 6A As shown, the treatment device 600 may include at least two main magnetic coils 601, at least two magnetic shielding coils 602, a cryostat 603 having an axis 605, a target 604, a first opening 607, a second opening 615, a groove 608, a linear accelerator 609, an MLC 610, a shielding structure 611, a collimator 612, and a deflection unit 613. The at least two main magnetic coils 601, the at least two magnetic shielding coils 602, the target 604, the axis 605, the first opening 607, the groove 608, the linear accelerator 609, the collimator 612, and the deflection unit 613 may be similar to the at least two main magnetic coils 501, the at least two magnetic shielding coils 502, the target 504, the axis 505, the opening 507, the groove 508, the linear accelerator 509, the collimator 512, and the deflection unit 513, and will not be repeated here.

[0128] and Figure 5A Compared to the MLC 510 shown in FIG. 5 , the MLC 610 can be located farther away from the linear accelerator 609 in the radial direction, so that the MLC 610 can be closer to, for example, a treatment area to be irradiated. It should be noted that the closer the distance between the MLC and the treatment area, the more accurately the shape of the radiation beam irradiated on the treatment area can be controlled by the MLC.

[0129] The cryostat 603 may have a concave structure at the inner wall of the cryostat 603 to accommodate the MLC 610. Similar to the groove 608, which has a first opening 607 formed between the outer walls of the two chambers of the cryostat 603, the concave structure may have a second opening 615 formed between the inner walls of the two chambers of the cryostat 603. The concave structure may have an annular shape and may be coaxial with the groove 608. The concave structure and the groove 608 may be separated by a neck of the cryostat 603. That is, the outermost surface of the neck forms the innermost boundary of the groove 608, and the innermost surface of the neck forms the outermost boundary of the concave structure. The concave structure may have a depth along the radial direction of the cryostat 603 that is greater than the height of the MLC 610 along the axis of the radiation beam. In some embodiments, one or more of the at least two main magnetic coils 601 (e.g., 601a) may be arranged to surround the concave structure along the axis 605. The main magnetic coil 601a and the remaining main magnetic coils in the left / right chamber of the cryostat 603 can form a step structure. The main magnetic coil 601a can have a radius from the axis 605 that is greater than the radius of the remaining main magnetic coils from the axis 605. In addition, a gap 606 can be formed between the main magnetic coils 601a to allow the radiation beam to pass through. In some embodiments, no main magnetic coil is arranged around the groove along the axis 605, and therefore, all main magnetic coils 601 can be arranged around the inner wall of the cryostat 603 and have the same radius as the axis 605.

[0130] Figure 6B FIG. 6 shows an upper portion of a cross-sectional view of an exemplary treatment device 600 ′ viewed along the X direction according to some embodiments of the present application. Fig. 6A Compared to the treatment device 600 described in the foregoing, at least a portion of the linear accelerator 609 of the treatment device 600' may be located outside the groove 608 along the radial direction of the cryostat 603. Figure 6B As shown, the linear accelerator 609, the shield structure 611, and the deflection unit 613 can at least partially extend out of the opening 607 formed by the outer wall of the cryostat 603. In some embodiments, the linear accelerator 609, the shield structure 611, and the deflection unit 613 can be supported by or mounted to a frame or roller (e.g., the frame 306 or the roller 312) and can rotate about the axis 605.

[0131] Fig. 7A 2 shows an upper portion of a cross-sectional view of another exemplary treatment device 600" viewed along the X direction according to some embodiments of the present application. Fig. 6ACompared to the treatment device 600 described in , the cryostat 603' of the treatment device 600" may have two independent chambers. The concave structure of the cryostat 603' can be connected to the groove 608 to form a larger annular space around the axis 605. In this case, no part of the cryostat 603 is located in the path of the radiation beam.

[0132] In some embodiments, various mechanisms may be used to achieve synchronous rotation of the linear accelerator and the MLC. Fig. 6A In the embodiment, a sliding structure (e.g., a slide rail, not shown) can be mounted on the MLC 610. When the linear accelerator 609 is rotated by the rack or rollers as described above, the MLC 610 can be synchronously moved along the inner wall of the cryostat 603 by the sliding structure to remain fixed relative to the linear accelerator 609. The movement of the MLC 610 can be controlled according to instructions generated by one or more processing engines 120. In addition, in Fig. 7A In the embodiment, the MCL 610 can be mechanically connected to the linear accelerator 609 via a rigid structure (e.g., two or more rods, one or more plates, not shown). In order to reduce the width of the groove 608 along the axis 605, the two or more rods can be arranged at different circumferential positions of the groove 608 relative to the linear accelerator 609. For example, when viewed along the axis 605, the two or more rods can be located on the left and right sides of the linear accelerator 609. It should be noted that the mechanism for achieving synchronous rotation of the linear accelerator and the MLC is not limited to the above description, and any modifications or adjustments can be made according to different scenarios. For example, in Fig. 7A In the embodiment, the MLC 610 can also move along the sliding structure to achieve synchronous rotation with the linear accelerator 609.

[0133] Figure 7B 2 shows an upper portion of a cross-sectional view of an exemplary treatment device 600'' viewed along the X direction according to some embodiments of the present application. Fig. 7A Compared to the treatment device 600" described in the foregoing, at least a portion of the linear accelerator 609 of the treatment device 600"' may be located outside the groove 608 in the radial direction of the cryostat 603'. Figure 7B As shown, the linear accelerator 609, the shielding structure 611, and the deflection unit 613 can at least partially extend out of the opening 607 formed by the outer wall of the cryostat 603'. In some embodiments, the linear accelerator 609, the shielding structure 611, and the deflection unit 613 can be supported by or mounted to a frame or roller (e.g., the frame 306 or the roller 312) and can rotate around the axis 605.

[0134] It should be noted that the description of the above-mentioned treatment device 600, 600', 600" or 600'" is provided for illustrative purposes only and is not intended to limit the scope of the present application. For those of ordinary skill in the art, various changes and modifications may be made based on the description of the present application. For example, the neck shown in the cryostat 603 may not form a complete ring. Specifically, the neck may be a discrete arc connecting the left chamber and the right chamber of the cryostat 603. Therefore, when the linear accelerator 609 rotates about the axis 605, the neck may intermittently appear in the path of the radiation beam to generate the radiation beam.

[0135] As described elsewhere in this application, MRI devices and radiotherapy devices may interfere with and impair the proper operation of each other. As an example only, the magnetic field generated by the main magnetic coil and magnetic shielding coil of the MRI device may interfere with the acceleration of the electron beam in the linear accelerator of the radiotherapy device. In order to prevent such interference, the above-mentioned shielding structure may include at least a magnetic shielding device to isolate the linear accelerator from the magnetic field. For simplicity, the magnetic shielding device should at least provide a passage near the linear accelerator that is easier for the magnetic field to pass through, so that the magnetic field can bypass the linear accelerator. In some embodiments, the magnetic shielding device may include one or more magnetic shielding structures, which are made of high magnetic susceptibility and / or magnetic permeability materials. One or more magnetic shielding structures may include at least one magnetic shielding plate or layer continuously distributed along the axial direction of the cryostat, providing a continuous passage for the magnetic field to pass through. One or more magnetic shielding structures may surround or substantially surround the linear accelerator, so that the magnetic field near the linear accelerator can be conducted through one or more magnetic shielding structures instead of the space where the linear accelerator is located. As used herein, substantially surrounding can mean that one or more slots can be formed on one or more magnetic shielding structures, provided that there is at least one continuous path along the axis of the cryostat to pass the magnetic field. More details regarding the configuration of the magnetic shielding device may be described below.

[0136] Fig. 8A A perspective view of an exemplary therapeutic device 800 is shown in accordance with some embodiments of the present application.

[0137] like Fig. 8A As shown, the treatment device 800 may include a hole 801, an annular cryostat 803 having an axis 805, a groove 808, a linear accelerator 809, and a magnetic shielding device. The cryostat 803, the axis 805, the groove 808, and the linear accelerator 809 may be similar to the cryostat 403, 403', 503, 503', 603 or 603', the axis 405, 505 or 605, the groove 408, 508 or 608, and the linear accelerator 409, 509 or 609, and will not be described again here.

[0138] The magnetic shielding device may include at least two magnetic shielding structures, including, for example, magnetic shielding structure 811, magnetic shielding structure 831a, magnetic shielding structure 831b, etc. The linear accelerator 809 may be surrounded or substantially surrounded by the magnetic shielding structure 811. The magnetic shielding structure 811 may include a first plate located on one side of the linear accelerator 809 along the circumferential direction of the groove 808 and a second plate located on the opposite side of the linear accelerator 809 along the circumferential direction of the groove 808. The first plate and the second plate may be symmetric to each other with respect to the axis of the linear accelerator 809. The first plate and the second plate may form a surrounding structure to surround and / or hold the linear accelerator 809. Each of the two plates may have a shape similar to the symbol "工", which provides a continuous path along the axial direction of the cryostat 803 (i.e., the direction of the axis 805) for the magnetic field to pass through. Since the two plates of the magnetic shielding structure 811 are made of a material with high magnetic susceptibility and / or permeability, the magnetic field can be conducted by the two plates and held in the region formed between them, thereby achieving magnetic shielding of the linear accelerator 809. In some embodiments, each of the two plates may be arranged radially around the axis 805, and at least one side of each of the two plates may point towards the axis 805.

[0139] In some embodiments, the first plate and the second plate may be connected to each other on both sides of the linear accelerator 809 along the axial direction of the cryostat 803, thereby forming a closed loop around the linear accelerator 809. In some embodiments, the first plate and the second plate may be separated from each other on both sides of the linear accelerator 809 along the axial direction of the cryostat 803, thereby forming a semi-closed loop that substantially surrounds the linear accelerator 809. It should be noted that the configuration of the magnetic shielding structure 811 is not limited, and any other configuration (such as a hollow cylinder or other shapes with curved sides) may also be used to achieve magnetic shielding.

[0140] In addition, the presence of the magnetic shielding structure 811 within the magnetic field of the MRI device may have an impact on the magnetic field (e.g., deforming the distribution and causing non-uniformity of the magnetic field). To correct the magnetic field deformation caused by the magnetic shielding structure 811, similar magnetic shielding structures of the magnetic shielding device, including magnetic shielding structure 831a, magnetic shielding structure 831b, etc., may also be placed within the groove 808. In some embodiments, all the magnetic shielding structures may be the same as each other. For example, the magnetic shielding structure 831a and the magnetic shielding structure 831b may be made of the same material and have the same structure as the magnetic shielding structure 811. The magnetic shielding structure 811, magnetic shielding structure 831a, magnetic shielding structure 831b, etc. may be mounted on the gantry or drum (not shown) of the treatment device 800 to achieve synchronous rotation with the linear accelerator 809.

[0141] In some embodiments, the magnetic shielding structure 811, the magnetic shielding structure 831a, the magnetic shielding structure 831b, etc. can be placed at selected symmetrical circumferential positions around the axis 805. For example, all magnetic shielding structures can be evenly distributed in the groove 808. Each magnetic shielding structure can correspond to a relative or opposite counterpart. Each magnetic shielding structure and its corresponding part can be symmetrical about the axis 805. As used herein, if two magnetic shielding structures are symmetrical about the axis 805, then the two magnetic shielding structures can be considered to be opposite or opposite.

[0142] Figure 8B A perspective view of an exemplary therapeutic device 800' is shown according to some embodiments of the present application. Fig. 8A Compared to the treatment device 800 described in the foregoing, at least a portion of the linear accelerator 809 of the treatment device 800' may be located outside the groove 808 along the radial direction of the cryostat 803. Figure 8B As shown, the linear accelerator 809 and the magnetic shielding structure 811 surrounding the linear accelerator 809 can extend out of the opening of the groove 808 formed by the outer wall of the cryostat 803. Similarly, the magnetic shielding structures 831a, 831b, etc. can also extend from the opening of the groove 808, thereby maintaining the symmetry of the magnetic shielding structure relative to the axis 805. In some embodiments, the linear accelerator 809 and all magnetic shielding structures can be supported by or mounted to a frame or drum (e.g., the frame 306 or the drum 312) that can rotate around the axis 805.

[0143] Fig.9A A cross-sectional view of a treatment device 800 viewed along the axial direction (i.e., Z direction) of a cryostat according to some embodiments of the present application is shown. The linear accelerator 809, collimator 812, and MLC 810 may be similar to the linear accelerator 409, 509, or 609, the collimator 412, 512, or 612, and the MLC 410, 510, or 610, and will not be described again here.

[0144] like Fig.9A As shown, the magnetic shielding structure 811, the magnetic shielding structure 821 and the magnetic shielding structures 831a, 831b, 831c, 831d can be evenly distributed in the groove 808 and around the axis 805 of the hole 801. The distance between each two adjacent magnetic shielding structures can be the same. The magnetic shielding structure 821 can be the opposite or opposite counterpart of the magnetic shielding structure 811. If the magnetic shielding structure 821 is rotated 180 degrees clockwise around the axis 805 to the position of the magnetic shielding structure 811, the magnetic shielding structure 821 can be the same as the magnetic shielding structure 811. All magnetic shielding structures can be fixed relative to the linear accelerator 809 and can therefore rotate synchronously with the linear accelerator 809.

[0145] Fig. 9B 800' according to some embodiments of the present application is a cross-sectional view of a treatment device 800' viewed along the axial direction (ie, Z direction) of a cryostat. Figure 8B As stated, Fig. 9B As shown, at least a portion of the linear accelerator 809 of the treatment device 800 ′ may be located outside the groove 808 in the radial direction of the cryostat 803 .

[0146] Fig. 10A A cross-sectional view of a treatment device 800 viewed along the Y direction according to some embodiments of the present application is shown.

[0147] Fig. 10B A cross-sectional view of a treatment device 800 ′ viewed along the Y direction according to some embodiments of the present application is shown.

[0148] It should be noted that the number of magnetic shielding structures in the magnetic shielding device is not limited. As long as the symmetry of the magnetic shielding structure is achieved, any number of magnetic shielding structures can be used in the treatment device. Fig.11A FIG. 1 shows a cross-sectional view of an exemplary treatment device 1100 having two magnetic shielding structures viewed along the X direction according to some embodiments of the present application. Fig.11A As shown, the treatment device 1100 may include at least two main magnetic coils 1101, at least two magnetic shielding coils 1102, a cryostat 1103 having an axis 1105, a groove 1108, a linear accelerator 1109, a first magnetic shielding structure 1111, a collimator 1112, a second magnetic shielding structure 1121 and a hole 1113. At least two main magnetic coils 1101, at least two magnetic shielding coils 1102, a cryostat 1103, an axis 1105, a groove 1108, a linear accelerator 1109 and a collimator 1112 may be similar to at least two main magnetic coils 401, 501 or 601, at least two magnetic shielding coils 402, 502 or 602, a cryostat 403, 403', 503, 503', 603, 603' or 803, an axis 405, 505, 605 or 805, a groove 408, 508, 608 or 808, a linear accelerator 409, 509, 609, or 809, and a collimator 412, 512, 612 or 812, and description thereof will not be repeated here.

[0149] The second magnetic shielding structure 1121 may be a relative or opposite counterpart of the first magnetic shielding structure 1111 and may be configured to reduce field inhomogeneities caused by the presence of the first magnetic shielding structure 1111. The second magnetic shielding structure 1121 and the first magnetic shielding structure 1111 may form a symmetrical structure within the magnetic field of the MRI device. That is, the second magnetic shielding structure 1121 may be located within the groove 1108 and may be located at a relative position of the first magnetic shielding structure 1111 relative to the axis 1105. The second magnetic shielding structure 1121 may be made of the same material as the first magnetic shielding structure 1111 and have the same structure as the first magnetic shielding structure 1111. For example, if the second magnetic shielding structure 1121 is rotated 180 degrees around the axis 1105 to the position of the first magnetic shielding structure 1111, the second magnetic shielding structure 1121 may be the same as the first magnetic shielding structure 1111.

[0150] Fig. 11B FIG. 1 shows an exemplary treatment device 1100 ′ having two magnetic shielding structures viewed along the X direction according to some embodiments of the present application. Fig.11A Compared to the treatment device 1100 described in the foregoing, at least a portion of the linear accelerator 1109 of the treatment device 1100' may be located outside the groove 1108 along the radial direction of the cryostat 1103. Fig. 11B As shown, the linear accelerator 1109, the first magnetic shielding structure 1111, and the second magnetic shielding structure 1121 can at least partially extend out of the opening of the groove 1108 formed by the outer wall of the cryostat 1103. The first magnetic shielding structure 1111 and the second magnetic shielding structure 1121 can still be symmetrical about the axis 1105. In some embodiments, the linear accelerator 1109, the first magnetic shielding structure 1111, and the second magnetic shielding structure 1121 can be supported by a frame or a drum (e.g., the frame 306 or the drum 312) or mounted to a frame or a drum (e.g., the frame 306 or the drum 312) to be able to rotate around the axis 1105.

[0151] Fig. 12A According to some embodiments of the present application, an upper portion of a cross-sectional view of a typical treatment device 1200 viewed along the X-axis direction is shown. Fig. 12AAs shown, the treatment device 1200 may include at least two main magnetic coils 1201, at least two magnetic shielding coils 1202, a cryostat 1203, a target 1204, an axis 1205, a gap 1206, a groove 1208, a linear accelerator 1209, an MLC 1210, a magnetic shielding structure 1211 and a collimator 1212. At least two main magnetic coils 1201, at least two magnetic shielding coils 1202, a cryostat 1203, a target 1204, an axis 1205, a gap 1206, a groove 1208, a linear accelerator 1209, an MLC 1210, and a collimator 1212 may be similar to at least two main magnetic coils 401, at least two magnetic shielding coils 402, a cryostat 403, 503, 603, 803, or 1103, a target 404, 504, or 604, an axis 405, 505, 605, 805, or 1105, a gap 406, 506, or 606, a groove 408, 508, 608, 808, or 1108, a linear accelerator 409, 509, 609, 809, or 1109, an MLC 410, 510, 610 or 810, and collimator 412, 512, 612, 812 or 1112, and descriptions thereof are not repeated here.

[0152] like Fig. 12A As shown, the magnetic shielding structure 1211 may include a first side plate 1211a, a second side plate 1211b, an upper side plate 1211c, and a lower side plate 1211d. The first side plate 1211a and the second side plate 1211b may be placed on opposite sides of the linear accelerator 1209 along the axial direction of the cryostat 1203 (i.e., along the direction of the axis 1205). The upper side plate 1211c and the lower side plate 1211d may be placed on opposite sides of the linear accelerator 1209 along the axial direction of the linear accelerator 1209. The first side plate 1211a, the second side plate 1211b, the upper side plate 1211c, and the lower side plate 1211d may form a closed loop around the linear accelerator 1209. If each plate is made of a material with high magnetic susceptibility and / or magnetic permeability, the magnetic field can bypass the linear accelerator 1209 and be conducted from one side of the cryostat 1203 to the other side of the cryostat 1203 (e.g., from the left side to the right side) along the axial direction of the cryostat 1203 by the upper side plate 1211c and the lower side plate 1211d, thereby achieving magnetic shielding for the linear accelerator 1209. The lower side plate 1211d may also provide at least one slot to allow a radiation beam generated by the linear accelerator 1209 to pass through.

[0153] Fig. 12B FIG. 1 shows an upper portion of a cross-sectional view of an exemplary treatment device 1200 ′ viewed along the X direction according to some embodiments of the present application. Fig. 12ACompared to the treatment device 1200 described in the foregoing, at least a portion of the linear accelerator 1209 of the treatment device 1200' may be located outside the groove 1208 along the radial direction of the cryostat 1203. Fig. 12B As shown, the linear accelerator 1209 and the magnetic shielding structure 1211 can at least partially extend out of the opening of the groove 1208 formed by the outer wall of the cryostat 1203. Specifically, the first side plate 1211a, the second side plate 1211b, and the upper side plate 1211c of the magnetic shielding structure 1211 can extend out of the opening of the groove 1208. In some embodiments, the linear accelerator 1209 and the magnetic shielding structure 1211 can be supported by or mounted to a frame or a drum (e.g., the frame 306 or the drum 312), which can rotate around the axis 1205.

[0154] Fig. 12C 1 shows an upper portion of a cross-sectional view of an exemplary treatment device 1200" viewed along the X direction according to some embodiments of the present application. Fig. 12A The treatment device 1200 described in Fig. 12B Compared to the treatment device 1200' described in the figure, the magnetic shielding structure 1211' of the treatment device 1200" can form a closed loop around the linear accelerator 1209, the collimator 1212 and the MLC 1210. Fig. 12C As shown, the first side plate 1211a' and the second side plate 1211b' can extend at least radially from the innermost radial position of the MLC 1210 to the outermost radial position of the linear accelerator 1209. The lower side plate 1211d' can be located at the innermost side of the MLC 1210, and at least one slot is also provided to allow the radiation beam generated by the linear accelerator 1209 to pass through. Therefore, the magnetic shielding structure 1211' can provide magnetic shielding for the linear accelerator 1209 and the MLC 1210.

[0155] Fig.13A FIG. 1 shows an upper portion of a cross-sectional view of an exemplary treatment device 1300 viewed along the X direction according to some embodiments of the present application. Fig. 12A Compared with the magnetic shielding structure 1211 described in the figure, the side plates 1211a” and 1211b” of the magnetic shielding structure 1211” can have grooves. The grooves can be of any shape, such as rectangular, elliptical, etc. It should be noted that the magnetic field can still be conducted by the upper side plate 1211c” and the lower side plate 1211d”, provided that the grooves are small enough to prevent the magnetic field from entering the linear accelerator 1209 through the grooves.

[0156] Fig. 13B FIG. 1 shows an upper portion of a cross-sectional view of an exemplary treatment device 1300 ′ viewed along the X-axis direction according to some embodiments of the present application. Fig.13ACompared to the treatment device 1300 described in the foregoing, at least a portion of the linear accelerator 1209 of the treatment device 1300' may be located outside the groove 1208 along the radial direction of the cryostat 1203. Fig. 13B As shown, the linear accelerator 1209 and the magnetic shielding structure 1211" can at least partially extend out of the opening of the groove 1208 formed by the outer wall of the cryostat 1203. Specifically, the first side plate 1211a", the second side plate 1211b" and the upper side plate 1211c" of the magnetic shielding structure 1211" can extend out of the opening of the groove 1208. In some embodiments, the linear accelerator 1209 and the magnetic shielding structure 1211" can be supported by or mounted to a frame or roller (e.g., frame 306 or roller 312), which can rotate around the axis 1205.

[0157] Fig. 13C 1 shows an upper portion of a cross-sectional view of an exemplary treatment device 1300" viewed along the X direction according to some embodiments of the present application. Fig.13A The treatment device 1300 described in Fig. 13B Compared to the treatment device 1300' described in the foregoing, the magnetic shielding structure 1211"' of the treatment device 1300" can surround the linear accelerator 1209, the collimator 1212 and the MLC 1210. Fig. 13C As shown, the first side plate 1211a'' and the second side plate 1211b'' can extend at least radially from the innermost radial position of the MLC 1210 to the outermost radial position of the linear accelerator 1209. The lower side plate 1211d'' can be located at the innermost side of the MLC 1210 and also provide at least one slot to allow the radiation beam generated by the linear accelerator 1209 to pass through.

[0158] Fig.14A A perspective view of an exemplary treatment device 1400 according to some embodiments of the present application is shown. Treatment device 1400 may include an aperture 1401, a magnet 1402 (similar to or identical to a "cryostat"), a linear accelerator 1409, and a magnetic shielding device. The magnetic shielding device may include a first magnetic shielding layer 1421, a second magnetic shielding layer 1422, and at least two magnetic shielding partitions (e.g., 1420a, 1420b, 1420c). Linear accelerator 1409, aperture 1401, and magnet 1402 may be similar to linear accelerators 409, 509, 609, 809, 1109, or 1209, aperture 301 or 801, and magnet 302, and description is not repeated here.

[0159] like Fig.14AAs shown, the first magnetic shielding layer 1421 can be located between the linear accelerator 1409 and one chamber of the magnet 1402, and the second magnetic shielding layer 1422 can be located between the linear accelerator 1409 and another chamber of the magnet 1402. The first magnetic shielding layer 1421 and the second magnetic shielding layer 1422 can have the same annular shape. The first magnetic shielding layer 1421 and the second magnetic shielding layer 1422 can be parallel to each other and coaxial with the hole 1401. The outer diameter of the first magnetic shielding layer 1421 can be equal to or greater than the outer diameter of the magnet 1402. The inner diameter of the first magnetic shielding layer 1421 can be greater than or equal to the inner diameter of the magnet 1402. The difference between the outer diameter and the inner diameter of the ring can be greater than or equal to the longitudinal length of the linear accelerator 1409.

[0160] Each of the at least two magnetic shielding partitions can be located between the first magnetic shielding layer 1421 and the second magnetic shielding layer 1422. Each of the at least two magnetic shielding partitions can connect the first magnetic shielding layer 1421 and the second magnetic shielding layer 1422. Every two adjacent magnetic shielding partitions (for example, magnetic shielding partition 1420e and magnetic shielding partition 1420f) can form a magnetic shielding structure with a portion of the first magnetic shielding layer 1421 and a portion of the second magnetic shielding layer 1422. The linear accelerator 1409 can be located in one of the magnetic shielding structures. Each magnetic shielding structure can have an opposite or relative counterpart. Each magnetic shielding structure and its corresponding portion can be symmetrical about the axis of the hole 1401.

[0161] At least two magnetic shielding baffles 1420 may be evenly or unevenly distributed between the first magnetic shielding layer 1421 and the second magnetic shielding layer 1422. In some embodiments, the number of the at least two magnetic shielding baffles 1420 may be a multiple of 2, forming an even-numbered magnetic shielding structure, thereby reducing the field inhomogeneity caused by the presence of the at least two magnetic shielding baffles 1420.

[0162] like Fig.14A As shown, the first magnetic shielding layer 1421, the second magnetic shielding layer 1422 and at least two magnetic shielding partitions can form a Fig. 8AA magnetic shielding structure similar to the magnetic shielding structure described in . For example, a portion of the first magnetic shielding layer 1421, a portion of the second magnetic shielding layer 1422, the magnetic shielding partition 1420f and the magnetic shielding partition 1420e can form a magnetic shielding structure similar to the magnetic shielding layer 811. The magnetic shielding partition 1420f and the magnetic shielding partition 1420e can provide a continuous path along the axial direction of the magnet 1402 to allow the magnetic field to pass through. For another example, a portion of the first magnetic shielding layer 1421, a portion of the second magnetic shielding layer 1422, the magnetic shielding partition 1420a and the magnetic shielding partition 1420b can form another magnetic shielding structure similar to the magnetic shielding layer 831a. As another example, a portion of the first magnetic shielding layer 1421, a portion of the second magnetic shielding layer 1422, the magnetic shielding partition 1420c and the magnetic shielding partition 1420d can form another magnetic shielding structure, similar to the magnetic shielding layer 831b.

[0163] Fig. 14B A perspective view of an exemplary therapeutic device 1400' is shown according to some embodiments of the present application. Fig.14A Compared to the treatment device 1400 described in the foregoing, at least a portion of the linear accelerator 1409 of the treatment device 1400' may be located outside the groove (not shown) along the radial direction of the magnet 1402. Fig. 14B As shown, the linear accelerator 1409 and the magnetic shielding device can at least partially extend out of the opening of the groove formed by the outer wall of the magnet 1402. Specifically, the first magnetic shielding layer 1421, the second magnetic shielding layer 1422 and at least two magnetic shielding partitions (e.g., 1420a, 1420b, 1420c) can extend out of the opening of the groove. In some embodiments, the linear accelerator 1409 and the magnetic shielding device can be supported by or mounted to a frame or drum (e.g., frame 306 or drum 312), which can rotate around the axis of the magnet 1402.

[0164] Fig.15A A perspective view of a treatment device 1500 according to some embodiments of the present application is shown. Treatment device 1500 may include aperture 1501, linear accelerator 1509, and a magnetic shielding device. The magnetic shielding device may include at least two magnetic shielding partitions (e.g., 1520a, 1520b, 1520c, 1520d, 1520e, 1520f), an inner magnetic shielding layer 1510, and an outer magnetic shielding layer 1530. Linear accelerator 1509 and aperture 1501 may be similar to linear accelerator 809 and aperture 801, such as Fig.9A As shown, the description is not repeated here.

[0165] like Fig.15AAs shown, the inner magnetic shield layer 1510 and the outer magnetic shield layer 1530 can be two hollow cylinders sharing the same axis. For example, when viewed along the axial direction of the hole 1501, the inner magnetic shield layer 1510, the outer magnetic shield layer 1530 and the hole 1501 can form concentric circles. The inner magnetic shield layer 1510 and the outer magnetic shield layer 1530 can be placed in the grooves described elsewhere in this application. The grooves can be similar to the grooves 408, 508 or 608, and can be configured to accommodate the linear accelerator 1509. The inner magnetic shield layer 1510 can be located at the innermost side of the depression and have a smaller radius than the outer magnetic shield layer 1530.

[0166] Each of the at least two magnetic shielding baffles (e.g., 1520a, 1520b, 1520c, 1520d, 1520e, 1520f) can be located between the inner magnetic shielding layer 1510 and the outer magnetic shielding layer 1530. For example, each of the at least two magnetic shielding baffles can connect the outer surface of the inner magnetic shielding layer 1510 and the inner surface of the outer magnetic shielding layer 1530. At least two magnetic shielding baffles can be arranged radially around the hole 1501. In some embodiments, each magnetic shielding baffle can point to the center of the hole 1501. Every two adjacent magnetic shielding baffles (e.g., magnetic shielding baffle 1520a and magnetic shielding baffle 1520b) can form a magnetic shielding structure with a portion of the inner magnetic shielding layer 1510 and a portion of the outer magnetic shielding layer 1530. The linear accelerator 1509 can be located in one of the magnetic shielding structures. Each magnetic shielding structure can have an opposite or relative counterpart. Each separate space and its counterpart can be symmetrical about the axis of the hole 1501. The magnetic shielding structures formed by the at least two magnetic shielding partitions can be the same or different. For example, at least two magnetic shielding partitions can be evenly distributed between the inner magnetic shielding layer 1510 and the outer magnetic shielding layer 1530, thereby forming at least two uniform magnetic shielding structures.

[0167] like Fig.15A As shown, when the linear accelerator 1509 is located inside the magnetic shielding structure formed by a portion of the inner magnetic shielding layer 1510, a portion of the outer magnetic shielding layer 1530, the magnetic shielding baffle 1520a, and the magnetic shielding baffle 1520b, the magnetic field can be conducted by the inner magnetic shielding layer 1510, the outer magnetic shielding layer 1530, the magnetic shielding baffle 1520a, and / or the magnetic shielding baffle 1520b, and is consistent with the linear accelerator 1509 located therebetween, thereby achieving magnetic shielding for the linear accelerator 1509. In some embodiments, in order to pass the radiation beam emitted from the linear accelerator 1509, the inner magnetic shielding layer 1510 can have one or more openings on the transmission path of the radiation beam.

[0168] In some embodiments, two or more magnetic shielding layers similar to magnetic shielding layer 1421 may be added to Fig.15AFor simplicity, Fig.14A The first magnetic shielding layer 1421 and the second magnetic shielding layer 1422 described in the embodiment of the present invention can be connected to the outer magnetic shielding layer 1530 at the outside thereof, and connected to both sides of the inner magnetic shielding layer 1510 at the inside thereof. Each of the at least two magnetic shielding partitions can connect the first magnetic shielding layer 1421 and the second magnetic shielding layer 1422 to form a magnetic shielding structure, and its cross-sectional view can be similar to Fig. 12A The cross-sectional view shown in . The diameter of the outer magnetic shield 1530 can be equal to or less than the outer diameter of the magnet 1402. The diameter of the inner magnetic shield 1510 can be equal to or greater than the inner diameter of the magnet 1402. The difference between the diameter of the outer magnetic shield 1530 and the diameter of the inner magnetic shield 1510 can be greater than or equal to the longitudinal length of the linear accelerator 1509.

[0169] Fig. 15B 1 shows a perspective view of a treatment device 1500' according to some embodiments of the present application. Fig.15A Compared to the treatment device 1500 described in the foregoing, at least a portion of the linear accelerator 1509 of the treatment device 1500' may be located outside the groove (not shown) along the radial direction of the magnet 1502. Fig. 15B As shown, the linear accelerator 1509 and the magnetic shielding device can at least partially extend out of the groove formed by the outer wall of the magnet 1502. Specifically, the outer magnetic shielding layer 1530 can have a radius larger than the radius of the magnet 1502. At least two magnetic shielding partitions (e.g., 1520a, 1520b, 1520c, 1520d, 1520e, 1520f) can extend from the opening of the groove. In some embodiments, the linear accelerator 1509 and the magnetic shielding device can be supported by or mounted to a frame or drum (e.g., frame 306 or drum 312), which can rotate around the axis of the magnet 1502.

[0170] Fig. 15C A perspective view of a therapeutic device 1500" according to some embodiments of the present application is shown. Fig.15ACompared to the treatment device 1500 described in the drawings, the magnetic shielding baffle of the treatment device 1500" may have a different configuration. Specifically, the magnetic shielding baffle 1520a' may have a shape of a strip or a rod. At least two parallel strips or rods may be used instead of the magnetic shielding baffle 1520 having a plate shape. At least two parallel strips or rods may connect a magnetic shielding layer 1521 located between a chamber of the linear accelerator 1509 and a cryostat (not shown) and another magnetic shielding layer (not shown) located between the linear accelerator 1509 and another chamber of the cryostat. It should be noted that the number of strips or rods at each circumferential position of the cryostat may be any suitable integer, such as 2, 3, 4, etc. The at least two parallel strips or rods may also provide a continuous channel along the axial direction of the hole 1501 for the magnetic field to pass through.

[0171] The magnetic shielding layer 1521 may also have at least two grooves thereon. Each groove may have a rectangular, elliptical, or other shape. Alternatively, at least two grooves may point to the axis of the hole 1501. At least two grooves may help to better dissipate the heat generated by the MRI device and / or the radiotherapy device. When a groove is provided between the shielding cover partition 1520a' and the magnetic shielding partition 1520b', the magnetic shielding structure may have a shape similar to Fig.13A Cross section shown.

[0172] Fig.15D A perspective view of a therapeutic device 1500"' is shown according to some embodiments of the present application. Fig. 15C Compared to the treatment device 1500" described in the embodiment of the present invention, at least a portion of the linear accelerator 1509 of the treatment device 1500"' can be located outside the groove (not shown) in the radial direction of the magnet 1502'. Fig.15D As shown, the linear accelerator 1509 and the magnetic shielding device can at least partially extend out of the groove formed by the outer wall of the magnet 1502'. Specifically, the outer magnetic shielding layer 1530' can have a larger radius than the magnet 1502'. At least two magnetic shielding partitions (e.g., 1520a', 1520b', 1520c', 1520d', 1520e', 1520f') can extend from the opening of the groove. In some embodiments, the linear accelerator 1509 and the magnetic shielding device can be supported by or mounted to a frame or drum (e.g., frame 306 or drum 312), which can rotate around the axis of the magnet 1502'.

[0173] Fig.16AA perspective view of an exemplary treatment device 1600 according to some embodiments of the present application is shown. The treatment device 1600 may include an aperture 1601, a linear accelerator 1609, and a magnetic shielding device. The magnetic shielding device may include at least two magnetic shielding partitions (e.g., 1620a, 1620b, 1620c, 1620d, 1620e, 1620f), an inner magnetic shielding layer 1610, and an outer magnetic shielding layer 1630. The inner magnetic shielding layer 1610, at least two magnetic shielding baffles (i.e., 1620a, 1620b, 1620c, 1620d, 1620e, 1620f), the linear accelerator 1609 and the hole 1601 can be similar to the inner magnetic shielding layer 1510, at least two magnetic shielding baffles (i.e., 1520a, 1520b, 1520c, 1520d, 1520e, 1520f), the linear accelerator 1509 and the hole 1501, and the description is not repeated here.

[0174] Unlike the outer magnetic shielding layer 1530, the outer magnetic shielding layer 1630 may not be continuous. Fig.16A As shown, the outer magnetic shielding layer 1630 may have at least two grooves at the contact surface of the outer magnetic shielding layer 1630 and at least two magnetic shielding partitions. The width of each groove in the circumferential direction may be equal to or greater than the thickness of the magnetic shielding partition. At least two grooves can help to better dissipate the heat generated by the MRI device and / or the radiotherapy device. In addition, at least two slots can also be used for cable layout. In some embodiments, similar grooves may also be present in the inner magnetic shielding layer 1610 for the same purpose.

[0175] Fig. 16B A perspective view of a treatment device 1600' is shown according to some embodiments of the present application. Fig.16A Compared to the treatment device 1600 described in the foregoing, at least a portion of the linear accelerator 1609 of the treatment device 1600' may be located outside the groove (not shown) along the radial direction of the magnet 1602. Fig. 16B As shown, the linear accelerator 1609 and the magnetic shielding device can at least partially extend out of the groove formed by the outer wall of the magnet 1602. Specifically, the outer magnetic shielding layer 1630 can have a larger radius than the magnet 1602. At least two magnetic shielding partitions (e.g., 1620a, 1620b, 1620c, 1620d, 1620e, 1620f) can extend from the opening of the groove. In some embodiments, the linear accelerator 1609 and the magnetic shielding device can be supported by or mounted to a frame or drum (e.g., frame 306 or drum 312), which can rotate around the axis of the magnet 1602.

[0176] 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 application. Although not explicitly stated here, those of ordinary skill in the art may make various modifications, improvements and amendments to this application. Such modifications, improvements and amendments are suggested in this application, so the modifications, improvements and amendments still belong to the spirit and scope of the exemplary embodiments of this application.

[0177] At the same time, the present application uses specific words to describe the embodiments of the present application. 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 the present application. 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, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0178] In addition, it will be appreciated by those skilled in the art that various aspects of the present application may be illustrated and described by a number of patentable categories or situations, including any new and useful combination of processes, machines, products or substances, or any new and useful improvements thereto. Accordingly, various aspects of the present application may be performed entirely by hardware, entirely by software (including firmware, resident software, microcode, etc.), or by a combination of hardware and software. The above hardware or software may all be referred to as "units", "modules" or "systems". In addition, various aspects of the present application may take the form of a computer program product embodied in one or more computer-readable media, wherein computer-readable program code is contained therein.

[0179] In addition, unless explicitly stated in the claims, the order of the processing elements and sequences described in this application, 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 application. 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 application. 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 software-only solution, for example, installation on an existing server or mobile device.

[0180] Similarly, it should be noted that in order to simplify the description disclosed in this application and thus facilitate the understanding of one or more embodiments of the invention, in the foregoing description of the embodiments of the present application, multiple features are sometimes grouped into one embodiment, figure, or description thereof. However, this method of the present application should not be interpreted as reflecting the intention that the claimed object material to be scanned requires more features than those expressly stated in each claim. On the contrary, the subject matter of the invention should have fewer features than the single embodiment described above.

[0181] In some embodiments, numbers describing the number of components and attributes are used. It should be understood that such numbers used in the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise specified, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may change according to the required features of individual embodiments. In some embodiments, the 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 the present application are approximate values, in specific embodiments, the setting of such numerical values ​​is as accurate as possible within the feasible range.

[0182] 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 descriptions, definitions, and / or term usage related to any incorporated material and those related to this document, the descriptions, definitions, and / or term usage in this document shall take precedence.

[0183] Finally, it should be understood that the embodiments described in this application are only used to illustrate the principles of the embodiments of the present application. Other variations may also fall within the scope of the present application. Therefore, as an example and not a limitation, the alternative configurations of the embodiments of the present application may be considered to be consistent with the teachings of the present application. Accordingly, the embodiments of the present application are not limited to the embodiments explicitly introduced and described in the present application.

Claims

1. A radiotherapy system comprising: A magnetic resonance imaging apparatus configured to acquire magnetic resonance imaging data about a region of interest, the magnetic resonance imaging apparatus comprising: at least two main magnetic coils; at least two magnetic shielding coils; An annular cryostat, wherein the at least two main magnetic coils and the at least two magnetic shielding coils are coaxially arranged along an axis of the annular cryostat, the at least two magnetic shielding coils are arranged at a greater radius from the axis than the at least two main magnetic coils, the annular cryostat comprising at least one outer wall and at least one inner wall coaxial with the axis of the annular cryostat, wherein the annular cryostat comprises: an annular groove having a first opening formed on the at least one outer wall and an annular concave structure having a second opening formed at the at least one inner wall; and A radiotherapy device, configured to radiotherapy at least a portion of the region of interest, the radiotherapy device comprising: a linear accelerator configured to accelerate electrons in the electron beam to produce a photon beam for radiation therapy, the linear accelerator being at least partially located within the annular recess of the cryostat; a target configured to receive the electrons to generate the radiation therapy photon beam; and a multi-leaf collimator received in the annular concave structure of the annular cryostat and configured to control a shape of the radiation therapy photon beam passing through the multi-leaf collimator; A first shielding structure is configured to provide magnetic shielding for the linear accelerator, wherein the first shielding structure forms a semi-closed loop around the axis of the linear accelerator, and the semi-closed loop includes at least two plates arranged along the circumferential direction of the linear accelerator.

2. The radiotherapy system according to claim 1, characterized in that The multi-leaf collimator is configured to move within the annular concave structure along a sliding structure.

3. The radiation therapy system according to claim 1, characterized in that One or more of the at least two main magnetic coils are arranged to surround the annular concave structure, and a radius of the one or more main magnetic coils from the axis is greater than a radius of the remaining main magnetic coils from the axis.

4. The radiation therapy system according to claim 1, characterized in that The annular groove is between the at least one outer wall and the at least one inner wall.

5. The radiation therapy system according to claim 1, characterized in that The multi-leaf collimator is connected to the linear accelerator via two or more rods.

6. The radiation therapy system according to claim 1, characterized in that The annular cryostat further comprises: At least two chambers and a neck, the at least two chambers are connected by the neck and are in fluid communication with each other, and the annular groove is defined by at least the at least two chambers and the neck.

7. The radiation therapy system according to claim 6, characterized in that The annular groove is located between the at least two chambers, and the outermost surface of the neck forms the innermost boundary of the annular groove.

8. The radiation therapy system according to claim 1, characterized in that The first shielding structure is continuously distributed along the axis direction of the linear accelerator, and extends along the axis direction of the linear accelerator to cover both ends of the linear accelerator.

9. The radiation therapy system according to claim 8, characterized in that The radiotherapy device further comprises at least one second shielding structure which is identical to the first shielding structure, wherein the first shielding structure and the at least one second shielding structure are respectively located at circumferential positions within the annular groove.

10. The radiation therapy system according to claim 9, characterized in that The first shielding structure and the at least one second shielding structure are evenly distributed in the annular groove.

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