CN218420685U

CN218420685U - Medical system

Info

Publication number: CN218420685U
Application number: CN202221547606.3U
Authority: CN
Inventors: 贺守波; 倪成; 傅费超; 汪鹏; 谢宗泰
Original assignee: Shanghai United Imaging Healthcare Co Ltd
Current assignee: Shanghai United Imaging Healthcare Co Ltd
Priority date: 2022-06-20
Filing date: 2022-06-20
Publication date: 2023-02-03
Anticipated expiration: 2032-06-20

Abstract

A medical system, comprising: a vacuum container (701) that surrounds and forms an accommodation space (602) extending in the axial direction; a main magnet (608) disposed within the vacuum vessel (701), the main magnet (608) including a first main magnetic field coil set (609) and a second main magnetic field coil set (610), and the first main magnetic field coil set (609) and the second main magnetic field coil set (610) being oppositely disposed on both sides of the accommodating space (602); and the radiation source (606) is arranged outside the vacuum container (701), and the projection of the radiation source (606) along the radial direction of the accommodating space at least partially falls into the area enclosed by the first main magnetic field coil group (609) or the area enclosed by the second main magnetic field coil group (610).

Description

Medical system

Technical Field

The present application relates generally to a medical system and, more particularly, to an image-guided radiation therapy system that combines radiation therapy and magnetic resonance imaging techniques.

Background

Currently, it is difficult to track changes (e.g., motion) of the tumor during different treatment stages, which affects the radiation therapy to the tumor. Today, various imaging techniques can provide images of tumors before or during each treatment. For example, a Magnetic Resonance Imaging (MRI) device may be used in conjunction with a radiotherapy apparatus to provide MRI images of a tumor. Since the particle accelerator of a radiotherapy apparatus generates X-rays or direct particle radiation by accelerating particle targeting, the particle beam is advanced in a straight line in the absence of an external magnetic field. Charged particles can deviate from a straight trajectory due to lorentz forces if there is magnetic field interference. In some cases, the magnetic field of the MRI apparatus may interfere with the proper operation of the particle accelerator, and the magnetic-containing components of the particle accelerator may also produce artifacts or image distortions in the MRI image. It is therefore desirable to provide a therapeutic system that can address the interference between the magnetic field of the MRI device and the accelerator charged particles.

SUMMERY OF THE UTILITY MODEL

One of the embodiments of the present specification provides a medical system, including: a vacuum container (701) that surrounds and forms an accommodation space (602) extending in the axial direction; a main magnet (608) disposed within the vacuum vessel (701), the main magnet (608) including a first set of main magnetic field coils (609) and a second set of main magnetic field coils (610), and the first set of main magnetic field coils (609) and the second set of main magnetic field coils (610) being oppositely disposed on both sides of the accommodating space (602); a radiation source (606) arranged outside the vacuum vessel (701), and a projection of the radiation source (606) in a radial direction of the receiving space at least partly falls within an area enclosed by the first set of main magnetic field coils (609) or within an area enclosed by the second set of main magnetic field coils (610).

In some embodiments, the first set (609) or second set (610) of main magnetic field coils includes a plurality of main magnetic field coils.

In some embodiments, a plurality of the primary magnetic field coils are arranged side by side along the axis direction.

In some embodiments, a plurality of the main magnetic field coils are nested.

In some embodiments, the main magnetic field coil comprises at least one of a saddle-type coil, a cos-theta type coil, or a racetrack type coil.

In some embodiments, the vacuum container (701) defines a first opening (601), the radiation source (606) is mounted in the first opening (601), and the radiation source (606) and the vacuum container (701) can rotate synchronously.

In some embodiments, the vacuum container (701) further comprises a probe, the vacuum container (701) is opened with a second opening (603), the probe is mounted on the second opening (603), and the first opening (601) and the second opening (603) are oppositely arranged on two sides of the accommodating space (602).

In some embodiments, the vacuum container (701) is mounted on the frame (605) so that the vacuum container (701) can rotate around the axial direction of the accommodating space (602) relative to the frame (605).

In some embodiments, further comprising at least two stands (605), wherein one stand (605) is used for fixing the radiation source (606) and the other stand is used for fixing the vacuum vessel (701).

In some embodiments, the main magnet (608) further comprises a first set of shield coils (903) and a second set of shield coils (904), and the first set of shield coils (903) is disposed within the vacuum vessel (701) outside of the first set of main magnetic field coils (609); the second set of shield coils (904) is arranged inside the vacuum vessel (701) outside the second set of main magnetic field coils (610).

Additional features of the present application will be set forth in part in the description which follows. Additional features of some aspects of the present application will be apparent to those of ordinary skill in the art in view of the following description and accompanying drawings, or in view of the production or operation of the embodiments. The features of the present application may be realized and attained by practice or use of the methods, instrumentalities and combinations of the various aspects of the specific embodiments described below.

Drawings

The present application will be further described by way of exemplary embodiments. These exemplary embodiments will be described in detail by means of the accompanying drawings. These embodiments are non-limiting exemplary embodiments in which like reference numerals refer to similar structures throughout the several views, and wherein:

fig. 1 is a block diagram of an exemplary medical system shown in accordance with some embodiments of the present application;

fig. 2 is an exemplary medical device shown according to some embodiments of the present application;

FIG. 3 is an exemplary racetrack coil;

FIG. 4 is a saddle coil shown according to some embodiments of the present application;

FIG. 5 is an illustration of a cos-theta type coil, in accordance with some embodiments of the present application;

FIG. 6 illustrates a saddle coil in relation to a central region of a receiving space according to some embodiments of the present application;

FIG. 7 illustrates the relationship of the racetrack coil to the central region of the containment space;

fig. 8 is an exemplary medical device shown according to some embodiments of the present application;

fig. 9 is an exemplary medical device shown according to some embodiments of the present application;

FIG. 10 is a schematic diagram illustrating an exemplary pass-to-cool mode according to some embodiments of the present application;

FIG. 11 is a cross-sectional schematic diagram illustrating an exemplary saddle coil according to some embodiments of the present application;

fig. 12 is a schematic diagram of an exemplary saddle-type shield coil shown according to some embodiments of the present application.

Reference numerals:

100: a medical system; 110: a medical device; 120: a processing engine; 130: a network; 140: a storage device; 150: a terminal device; 151: a mobile device; 152: a tablet computer; 153: a laptop computer;

200: an MRI device; 201: an accommodating space; 202: a main magnet; 203: a target object; 204: a hospital bed;

300-1: a race type coil; 303-306: a bent portion of the racetrack coil 300-1; 307: the plane corresponding to the bending direction of the bending parts 303-306; 300-2, 300-4: a saddle coil; 301-302: the bent portion of saddle coil 300-2; 308: a plane corresponding to the bending direction of the bending portion 301; 309: a plane corresponding to the bending direction of the bent portion 302; 300-3, 300-5: a cos-theta type coil; 310-311: a bent portion of the cos-theta type coil 300-3; 312: a plane corresponding to the bending direction of the bent portion 310; 313: a plane corresponding to the bending direction of the bent portion 311;

400-1: a saddle coil; 400-2: a racetrack coil; 401. 404: the sides of saddle coil 400-1; 402: a central region of the accommodation space; 403: the distance of the edge 404 from the center area 402; 405. 406: the sides of the racetrack coil 400-2; 407: the distance of the edge 406 from the center region 402;

510: an MRI device; 520: a radiotherapy apparatus;

600: an MRI device; 601: a first opening; 602: an accommodating space; 603: a second opening; 604: a cooling device; 605: a frame; 606: a radiation source; 607: a target object; 608: a main magnet; 609: a first set of main magnetic field coils; 610: a second set of main magnetic field coils; 613: a hospital bed;

701: a vacuum vessel; 702: a superconducting magnet; 703: a shielding layer; 704: a primary cold head end plate of the refrigerator; 705: a secondary cold head end plate of the refrigerator; 706: a cold conducting structure; 707: a refrigerator;

800: a saddle coil; 801: a first set of main magnetic field coils; 802: a second set of main magnetic field coils; 803: a cross-section; 804: a sphere volume center region corresponding to cross section 804; 805: an accommodation space axis;

901: a first set of main magnetic field coils; 902: a second set of main magnetic field coils; 903: a first shield coil group; 904: and a second shield coil group.

Detailed Description

The following description is presented to enable one of ordinary skill in the art to make and use the invention and is provided in the context of a particular application and its requirements. It will be apparent to those of ordinary skill in the art that various changes can be made to the disclosed embodiments and that the general principles defined in this application can be applied to other embodiments and applications without departing from the principles and scope of the application. Thus, the present application is not limited to the described embodiments, but should be accorded the widest scope consistent with the claims.

The terminology used in the description presented herein is for the purpose of describing particular example embodiments only and is not intended to limit the scope of the present application. As used in this application and the appended claims, the terms "a," "an," "the," and/or "the" are not intended to be inclusive in the singular, but rather are intended to be inclusive in the plural unless the context clearly dictates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, components, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, components, and/or groups thereof.

These and other features, aspects, and characteristics of the present application, as well as the methods of operation and functions of the related elements of structure and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following description of the accompanying drawings, all of which form a part of this specification. It is to be understood, however, that the drawings are designed solely for the purposes of illustration and description and are not intended as a definition of the limits of the application. It should be understood that the figures are not drawn to scale.

Fig. 1 is a block diagram of an exemplary medical system 100 shown according to some embodiments of the present application.

As shown in fig. 1, medical system 100 may include a medical apparatus 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 medical apparatus 110, the one or more processing engines 120, the storage 140, and/or the terminal device 150 may be connected and/or communicate with each other through 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.

In some embodiments, the medical system 100 may include an imaging system. The imaging system may include a single modality imaging system and/or a multi-modality imaging system. The single modality imaging system may include a Magnetic Resonance Imaging (MRI) system. The multi-modality imaging system may include a computed tomography-magnetic resonance imaging (MRI-CT) system, a positron emission tomography-magnetic resonance imaging (PET-MRI) system, a single photon emission computed tomography-magnetic resonance imaging (SPECT-MRI) system, a digital subtraction angiography-magnetic resonance imaging (DSA-MRI) system, and the like. In some embodiments, the medical system 100 may include a therapy system. The treatment system may include a Treatment Planning System (TPS), image Guided Radiation Therapy (IGRT), and the like. Image Guided Radiation Therapy (IGRT) may include a treatment device and an imaging device. The treatment device may comprise a linear accelerator, a cyclotron, a synchrotron or the like, configured to deliver radiation treatment to the subject. The treatment device may comprise an accelerator for particle species including, for example, photons, electrons, protons or heavy ions. The imaging device may include an MRI scanner or the like.

The medical apparatus 110 may include a magnetic resonance imaging component (hereinafter referred to as "MRI device"). The MRI apparatus may generate image data associated with magnetic resonance signals (hereinafter, referred to as "MRI signals") by scanning a subject or a portion of the subject. In some embodiments, the object may comprise a body, a substance, an object, or the like, or any combination thereof. In some embodiments, the object may include a particular part of the body, a particular organ, or a particular tissue, such as the head, brain, neck, body, shoulders, arms, chest, heart, stomach, blood vessels, soft tissue, knee, feet, or the like, or any combination thereof. In some embodiments, the medical apparatus 110 may transmit the image data to one or more processing engines 120, storage 140, and/or terminal device 150 via the network 130 for further processing. For example, the image data may be sent to one or more processing engines 120 to generate MRI images, or may be stored in storage device 140.

The medical apparatus 110 may further include a radiation therapy component (hereinafter referred to as a "radiation therapy device"). The radiotherapy device may provide radiation for treatment of a target region (e.g. a tumour). Radiation as used herein may include particle rays, photon rays, and the like. The particle rays may include neutrons, protons, electrons, muons, heavy ions, alpha rays, etc., or any combination thereof. The photon rays may include X-rays, gamma rays, ultraviolet rays, laser light, and the like, or any combination thereof. In some embodiments, the radiotherapy device may generate a dose of radiation to perform radiotherapy with the aid of image data provided by the MRI device. For example, the image data may be processed to locate a tumor and/or determine a dose of radiation.

The one or more processing engines 120 may process data and/or information obtained from the medical apparatus 110, the storage 140, and/or the terminal device 150. For example, the one or more processing engines 120 may process the image data and reconstruct at least one MRI image based on the image data. For another example, the one or more processing engines 120 can determine the location and radiation dose of the treatment region based on the at least one MRI image. MRI images have the advantage of providing, for example, excellent soft tissue contrast, high resolution, geometric accuracy, and the ability to precisely locate the treatment region. The MRI images may be used to detect changes in the treatment area (e.g., tumor regression or metastasis) during the determination of the treatment plan and the execution of the treatment, so that the original treatment plan may be adjusted accordingly. The original treatment plan may be determined before treatment begins. For example, the original treatment plan may be determined at least one day, three days, one week, two weeks, one month, etc. before treatment begins.

In some embodiments, the one or more processing engines 120 may be a single processing engine that communicates with the medical device 110 and processes data from the MRI apparatus and/or the radiation therapy apparatus. Alternatively, the one or more processing engines 120 can include at least two processing engines. One of the at least two processing engines may communicate with the MRI equipment of medical device 110 and process data, and another of the at least two processing engines may communicate with the radiation therapy equipment of medical device 110 and process data. In some embodiments, the one or more processing engines 120 may include a treatment planning system. At least two processing engines may be in communication with each other.

In some embodiments, one or more processing engines 120 may be a single server or a group of servers. The server groups may be centralized or distributed. In some embodiments, the one or more processing engines 120 may be local or remote to the medical device 110. For example, one or more processing engines 120 may access information and/or data from medical apparatus 110, storage 140, and/or terminal device 150 via network 130. As another example, one or more processing engines 120 may be directly connected to medical apparatus 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 private clouds, public clouds, hybrid clouds, community clouds, distributed clouds, inter-cloud, multi-cloud, and the like, or any combination thereof.

Network 130 may include any suitable network that may facilitate the exchange of information and/or data for medical system 100. In some embodiments, one or more components of medical system 100 (e.g., medical device 110, one or more processing engines 120, storage 140, or terminal device 150) may communicate information and/or data with one or more other components of medical system 100 via network 130. For example, one or more processing engines 120 may obtain image data from medical device 110 via network 130. As another example, one or more processing engines 120 may obtain user instructions from end device 150 via 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, 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 medical system 100 may connect to network 130 to exchange data and/or information.

Storage device 140 may store data, instructions, and/or any other information. In some embodiments, storage device 140 may store data obtained from one or more processing engines 120 and/or end devices 150. In some embodiments, storage device 140 may store data and/or instructions that one or more processing engines 120 may perform or use to perform the example methods described herein. In some embodiments, storage device 140 may include mass storage devices, removable storage devices, cloud-based storage devices, volatile read-write memory, read-only memory (ROM), etc., or any combination thereof. Exemplary mass storage may include magnetic disks, optical disks, solid state drives, and the like. Exemplary removable memory may include flash drives, floppy disks, optical disks, memory cards, compact disks, magnetic tape, and the like. Exemplary volatile read and write memory can include Random Access Memory (RAM). Exemplary RAM may include Dynamic RAM (DRAM), double-data-rate synchronous dynamic RAM (DDR SDRAM), static RAM (SRAM), thyristor RAM (T-RAM), zero-capacitor RAM (Z-RAM), and so forth. Exemplary ROMs may include Mask ROM (MROM), programmable ROM (PROM), erasable Programmable ROM (EPROM), electrically Erasable Programmable ROM (EEPROM), compact disk ROM (CD-ROM), digital versatile disk ROM, and the like. In some embodiments, storage device 140 may be provided on a cloud platform as described elsewhere in this application.

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

Terminal device 150 may be connected to and/or in communication with medical apparatus 110, one or more processing engines 120, and/or storage device 140. For example, one or more processing engines 120 may obtain a scanning protocol from terminal device 150. As another example, terminal device 150 may obtain image data from medical apparatus 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, or the like, or any combination thereof. For example, 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, terminal device 150 may include an input device, an output device, and the like. The input devices may include alphanumeric and other keys that may be entered via a keyboard, touch screen (e.g., with tactile or haptic feedback), voice input, eye-tracking input, brain-monitoring system, or any other similar input mechanism. Input information received through the input device may be transmitted, via a bus for example, to one or more processing engines 120 for further processing. Other types of input devices may include cursor control devices such as a mouse, a trackball, or cursor direction keys. Output devices may include a display, speakers, printer, etc., or any combination thereof. In some embodiments, end device 150 may be part of one or more processing engines 120.

The description is intended to be illustrative, and not to limit the scope of the application. Many alternatives, modifications, and variations will be 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 store comprising a cloud computing platform, such as a public cloud or the like. In some embodiments, one or more processing engines 120 may be integrated into medical device 110. However, such changes and modifications do not depart from the scope of the present application.

Fig. 2 is an illustrative medical device according to some embodiments of the present application. The medical apparatus may include an MRI device 200. As shown in fig. 2, the MRI apparatus 200 may include an accommodation space 201, a main magnet 202, one or more gradient coils (not shown), and one or more Radio Frequency (RF) coils (not shown).

The X, Y and Z axes shown in fig. 2 may form an orthogonal coordinate system. As shown in FIG. 2, the X-axis and Z-axis may be horizontal and the Y-axis may be vertical. As shown in fig. 2, the positive direction of the X-axis may be from the right side to the left side of the MRI apparatus 200, as viewed from the direction facing the front of the MRI apparatus 200; the positive direction of the Y-axis may be from the lower portion to the upper portion of the MRI apparatus 200; the positive direction of the Z-axis may refer to a direction in which the target object 203 is moved out of the accommodation space 201 of the MRI apparatus 200, pointing from the back to the front of the MRI apparatus 200.

In some embodiments, MRI device 200 may be a permanent magnet MRI scanner, a superconducting electromagnet MRI scanner, or a resistive electromagnet MRI scanner, among others, depending on the type of main magnet 202. In some embodiments, depending on the strength of the magnetic field, the MRI apparatus 200 may be a high-field MRI scanner, a mid-field MRI scanner, a low-field MRI scanner, and the like. In some embodiments, the MRI apparatus 200 may be a closed-bore (cylindrical) type, an open-bore type, or the like.

The main magnet 202 can generate a static magnetic field B0 through at least one main magnetic field coil. The main magnet 202 may be of various types including, for example, a permanent magnet, a superconducting electromagnet, a resistive electromagnet, and the like. Superconducting electromagnets may include niobium, vanadium, technetium alloys, or copper oxides, among others. The main magnet 202 forms an accommodating space 201 extending in an axial direction (for example, a Z direction shown in fig. 2) for accommodating a target object 203. In some embodiments, the main magnet 202 can be annular in shape, as can other shapes.

One or more gradient coils may generate magnetic field gradients in the X, Y, and/or Z directions. The magnetic field gradients can be superimposed on the main magnetic field generated by the main magnet 202 and distort the main magnetic field such that the magnetic orientation of the protons of the object can be varied according to their position within the gradient fields, thereby spatially encoding the MR signals. In some embodiments, one or more gradient coils may include X-direction (or axis) coils, Y-direction (or axis) coils, Z-direction (or axis) coils, and the like.

One or more RF coils can transmit RF pulses to and/or receive MR signals from a target object (e.g., a body, a substance, an object). In some embodiments, the RF coil may include an RF transmit coil and/or an RF receive coil. The RF transmit coil may transmit RF pulse signals that may excite nuclei in the subject to resonate at the larmor frequency. The RF receive coil may receive MR signals transmitted from a subject. In some embodiments, the RF transmit coil and the RF receive coil may be integrated into a single coil, e.g., a transmit/receive coil. The RF coil may be one of various types, such as a quadrature coil, a phased array coil, and the like. In some embodiments, different RF coils 240 may be used to scan different parts of the subject, e.g., head coils, knee coils, cervical coils, thoracic coils, temporomandibular joint (TMJ) coils, etc. In some embodiments, the RF coil may be divided into a volume coil and a local coil depending on its function and/or size. For example, the volume coils may include birdcage coils, transverse electromagnetic coils, surface coils, and the like. Also for example, the local coil may include a solenoid coil, saddle coil, flexible coil, or the like.

In some embodiments, the MRI apparatus 200 may further include a patient bed 204. In some embodiments, at least a portion of the patient bed 204 is movable in the Z-direction and into the receiving space 201 of the MRI apparatus 200. In some embodiments, the target object 203 may be placed on a patient bed 204 and brought into the accommodation space 201. In some embodiments, at least a portion of the patient's bed 204 may also be moved in two, three, four, five, or six dimensions.

In some embodiments, the main magnetic field coils of the main magnet 202 can have a planar shape or can have a three-dimensional shape that is not in the same plane. In some embodiments, the main magnetic field coil has at least two meandering portions having meandering directions that correspond to different planes. The bending direction of the bent portion may refer to an extending direction or a tangential direction of both ends of the bent portion.

For example, as shown in fig. 3, the racetrack coil 300-1 has a planar shape. The racetrack main magnetic field coil 300-1 includes

bent portions

303, 304, 305, and 306. The bending directions of the

bent portions

303, 304, 305, and 306 are shown by arrows in fig. 3. It can be seen that the bending directions of the

bent portions

303, 304, 305, and 306 of the racetrack coil 300-1 correspond to the same plane 307 (shown by the dashed box in fig. 3). As shown in fig. 4, the saddle-type main magnetic field coils 300-2 have three-dimensional shapes that are not on the same plane. Saddle-type main magnetic field coil 300-2 includes at least bent portions 301 and 302. The bending direction of the bent portions 301 and 302 is shown by arrows in fig. 4. The meandered portion 301 of saddle-type main magnetic field coil 300-2 corresponds to plane 308 and the meandered portion 302 of saddle-type main magnetic field coil 300-2 corresponds to plane 309.

As shown in fig. 5, the cos-theta type main magnetic field coil 300-3 has a three-dimensional shape that is not on the same plane. The cos-theta type main magnetic field coil 300-3 includes at least

bent portions

310 and 311. The bending direction of the

bent portions

310 and 311 is shown by arrows in fig. 5. The meander portion 310 of the cos-theta type main magnetic field coil 300-3 corresponds to plane 312 and the meander portion 311 of the cos-theta type main magnetic field coil 300-3 corresponds to plane 313.

In some embodiments, the main magnetic field coils of the main magnet 202 may include at least one of a racetrack coil 300-1, saddle coil 300-2, or cos-theta type coil 300-3.

In some embodiments, the main magnet 202 may comprise a first set of main magnetic field coils and a second set of main magnetic field coils disposed opposite each other in a radial direction of the accommodating space 201, which first set of main magnetic field coils and/or which second set of main magnetic field coils may comprise at least one of said main magnetic field coils. For example, as shown in fig. 4, the main magnet 202 may include a first main magnetic field coil set including a saddle coil 300-2 and a second main magnetic field coil set including a saddle coil 300-4 oppositely disposed in a radial direction of the accommodating space 201, with the accommodating space 201 being located between the saddle coil 300-2 and the saddle coil 300-4. Also for example, the first set of main magnetic field coils may include a cos-theta type coil 300-3, the second set of main magnetic field coils may include a cos-theta type coil 300-5, and the receiving space 201 is located between the cos-theta type coil 300-3 and the cos-theta type coil 300-5. The Z direction in fig. 4 and 5 corresponds to the Z direction in fig. 2.

In some embodiments, the shape of the main magnetic field coils of the main magnet 202 can be the same or different. For example, the main magnetic field coils of the main magnet 202 may all be saddle type coils or cos-theta type coils. Also for example, the first main magnetic field coil set includes saddle-type coils and cos-theta type coils. As another example, the first set of main magnetic field coils includes saddle-type coils and the second set of main magnetic field coils includes cos-theta type coils.

In some embodiments, at least two of the first and/or second sets of primary magnetic field coils may be arranged stacked in a radial direction of the receiving space 201. In some embodiments, at least two of the first and/or second sets of primary magnetic field coils may be arranged circumferentially and/or axially tiled along the receiving space 201. In some embodiments, at least two of the primary magnetic field coils of the first set of primary magnetic field coils and/or the second set of primary magnetic field coils can be nested (as shown in fig. 12). In some embodiments, at least two of the main magnetic field coils can be connected in series. For example, at least two main magnetic field coils are connected by superconducting joints.

In some embodiments, the first and second sets of radially oppositely disposed main magnetic field coils can form a dipole field region between the first and second sets of main magnetic field coils (e.g., in the receiving space 201) to generate a main magnetic field at a predetermined angle (e.g., greater than 0 degrees and less than or equal to 90 degrees) to an axial direction (e.g., Z direction), e.g., to generate a main magnetic field perpendicular to the axial direction (e.g., Z direction).

If a racetrack-type coil is made into a coil with a three-dimensional shape which is not on the same plane, compared with the racetrack-type coil, the projected area of the coil with the three-dimensional shape which is not on the same plane along the main magnetic field direction is smaller than that of the racetrack-type coil, and according to the magnetic flux principle, the smaller the area of the magnetic field lines passing through the racetrack-type coil is, the larger the magnetic field intensity is, under the condition that the magnetic flux is constant (for example, the current flowing through the coil is consistent). That is, coils with three-dimensional shapes that are not in the same plane can produce stronger or larger shimming areas magnetic fields with the same mass of the coil; on the other hand, if it is desired to generate magnetic fields of the same strength or the same shim area, coils having three-dimensional shapes that are not in the same plane will be required to be of a smaller mass than racetrack-type coils, and the smaller coil mass will make the MRI apparatus more portable.

Further, taking a saddle coil as an example, as shown in fig. 6 and 7, if the distance between the side 401 of the saddle coil 400-1 and the central region 402 of the accommodation space 201 is equal to the distance between the side 405 of the racetrack coil 400-2 and the central region 402 of the accommodation space 201, and the side 404 of the saddle coil 400-1 can be regarded as being bent in a direction close to the central region 402 so that the saddle coil 400-1 has a three-dimensional shape that is not on the same plane, the bent side 404 of the saddle coil 400-1 is closer to the central region 402 (the distance 403 is smaller than the distance 407) than the side 406 of the racetrack coil 400-2, and therefore the contribution of the bent side 404 of the saddle coil 400-1 to the central field is higher than the contribution of the side 406 of the racetrack coil 400-2.

In some embodiments, the main magnetic field may have a uniformity of better than 1 ppm over a range. In this range, the main magnetic field maintains high homogeneity with active and passive shimming components. In some embodiments, the range may be a volumetric region centered at the center of the MRI device imaging field of view, such as a spherical volume region, a cube region, a cuboid region, a cylindrical region, an ellipsoid region, and the like. For example, the range may be a spherical volume region centered at the center of the MRI apparatus imaging field of view and having a diameter greater than 50 cm.

As an example, as shown in fig. 11, taking a saddle coil as an example, the saddle coil 800 includes a first main magnetic field coil group 801 and a second main magnetic field coil group 802 that are oppositely disposed in the radial direction. A dipole field region may be formed between the first and second main magnetic field coil sets 801 and 802 to generate a main magnetic field at a preset angle (e.g., greater than 0 degrees and 90 degrees or less) to the axis direction 805 (e.g., corresponding to the Z direction), for example, to generate a main magnetic field perpendicular to the axis direction. For example, as shown in fig. 11, a current in a clockwise direction (as shown by an arrow direction in fig. 11) is passed through the first main magnetic field coil set 801 and the second main magnetic field coil set 802, and a magnetic field as shown in fig. 11 can be generated in the cross section 803. The cross section 803 is perpendicular to the axis 805 and is located in the middle of the saddle coil 800 in the direction of the axis 805. The homogeneity of the magnetic field generated by the first set of main magnetic field coils 801 and the second set of main magnetic field coils 802 is better than 1 ppm in a sphere volume region. The spherical volume region is centered in the receiving space formed by the first set of main magnetic field coils 801 and the second set of main magnetic field coils 802, with the axis 805 passing through the center of the sphere of the spherical volume region. Region 804 is the sphere volume center region of the sphere volume region corresponding to section 803.

In some embodiments, the MRI apparatus 200 includes a vacuum vessel that surrounds to form a receiving space extending in the axial direction. A main magnet 202 is disposed within the vacuum vessel.

In some embodiments, the main magnet 202 can also include at least one shielding coil. The shield coils may serve to protect the main magnetic field from external influences and also to limit the spread of the main magnetic field in the ambient environment by means of stray magnetic fields. In some embodiments, the direction of the current passing through the shield coil is opposite to the direction of the current passing through the main magnetic field coil, so that the shield coil generates an opposite magnetic field to cancel the stray magnetic field of the main magnetic field, thereby shielding the magnetic field.

In some embodiments, the shield coil may include a first shield coil group and a second shield coil group disposed diametrically opposite to each other along the accommodation space, and be located inside the vacuum vessel. A first set of shield coils corresponds to the first set of main magnetic field coils and is located outside the first set of main magnetic field coils (e.g., on a side of the first set of main magnetic field coils radially away from the axis of the receiving space), and a second set of shield coils corresponds to the second set of main magnetic field coils and is located outside the second set of main magnetic field coils. In some embodiments, the first and second shield coil sets may be nested outside of the first and second main magnetic field coil sets, respectively. In some embodiments, the shape of the shield coils and the shape of the main magnetic field coils may be the same, e.g., both saddle coils or cos-theta type coils.

In some embodiments, the first and second shield coil sets may each include at least one shield coil. In some embodiments, at least two shield coils of the first shield coil group and/or the second shield coil group may be stacked in a radial direction of the accommodating space. In some embodiments, at least two of the primary magnetic field coils of the first and/or second shield coil sets may be arranged in a circumferential and/or axial tiling of the receiving space. In some embodiments, at least two of the main magnetic field coils of the first set of shield coils and/or the second set of shield coils may be nested.

As shown in fig. 12, taking a saddle coil as an example, the first main magnetic field coil group 901 and the second main magnetic field coil group 902 respectively include 3 saddle-shaped main magnetic field coils which are nested. The first shield coil set 903 and the second shield coil set 904 are disposed diametrically opposite to each other. A first set of shield coils 903 corresponds to the first set of main magnetic field coils 901 and a second set of shield coils 904 corresponds to the second set of main magnetic field coils 902. The first shielding coil set 903 and the second shielding coil set 904 respectively include 1 saddle-shaped shielding coil, and are respectively sleeved outside the first main magnetic field coil set 901 and the second main magnetic field coil set 902.

Fig. 8 is an illustrative medical device according to some embodiments of the present application. As shown in fig. 8, the medical apparatus may include an MRI device 510 and a radiotherapy device 520. In some embodiments, the MRI apparatus 200 described in fig. 2 may be applied to the MRI apparatus 510. The X, Y, and Z directions in fig. 8 correspond to the X, Y, and Z directions in fig. 2.

The radiation therapy device 520 may include a radiation source disposed outside of the vacuum vessel. The radiation source is for transmitting a therapeutic beam to at least a portion of a region of interest of the target subject. The treatment beam may include particle rays, photon rays, and the like. The particle rays may include neutrons, protons, electrons, muons, heavy ions, alpha rays, etc., or any combination thereof. The photon rays may include X-rays, gamma rays, ultraviolet rays, laser light, and the like, or any combination thereof. In some embodiments, the radiotherapy device 520 can further comprise a detector (not shown) configured to receive the therapeutic beam, the detector being disposed radially opposite the radiation source and rotatable with the radiation source.

It should be noted that the foregoing is provided for illustrative purposes only and is not intended to limit the scope of the present application. Many variations and modifications are possible to those skilled in the art in light of the teachings herein. For example, the radiation therapy apparatus 520 may further include a linear accelerator configured to accelerate electrons, ions, or protons, a dose detection device, a temperature control device (e.g., a cooling device), a multi-layer collimator, or the like, or any combination thereof. However, such changes and modifications do not depart from the scope of the present application.

In some embodiments, the radiation source emits a therapeutic beam in a direction perpendicular to the axial direction of the receiving space. In this application, the direction of the treatment beam emitted by the radiation source refers to the axial direction of the treatment beam. In some embodiments, the main magnet of the MRI device 510 may be rotated synchronously with the radiation source about the axial direction of the receiving space, such that a projection of the radiation source in a radial direction of the receiving space at least partially falls within the region enclosed by the first set of main magnetic field coils or within the region enclosed by the second set of main magnetic field coils. Alternatively, as shown in fig. 8, the main magnet of the MRI apparatus 510 may be rotated synchronously with the radiation source around the axial direction of the accommodating space, so that the direction of the treatment beam emitted by the radiation source is always the same as the main magnetic field direction B0. In some embodiments, the main magnetic field may have a uniformity of better than 1 ppm over a range. Within this range, the direction of the main magnetic field is kept in line with the direction of the therapeutic beam emitted by the radiation source, and a higher homogeneity is maintained, provided that shimming is active and passive. In some embodiments, the range may be a volumetric region centered at the center of the field of view imaged by MRI device 510, such as a spherical volume region, a cube region, a cuboid region, a cylindrical region, an ellipsoid region, and the like. For example, the range may be a spherical volume region centered at the center of the MRI device 510 imaging field of view and greater than 50cm in diameter. By way of example only, the main magnet and the radiation source of the MRI device 510 may be axially rotated by any angle, such as 90 degrees, 180 degrees, 360 degrees, 450 degrees, 540 degrees. In the radiotherapy process, the MRI equipment and the radiotherapy equipment rotate together, so that the functions of real-time image guidance and the like in treatment can be realized.

In some embodiments, the radiotherapy device 520 and the MRI device 510 may rotate together. For example, the radiation therapy device 520 and the MRI device 510 may be mounted on the same gantry, with the gantry rotating together. In some embodiments, the radiotherapy device 520 and the MRI device 510 can rotate independently, e.g., the radiotherapy device 520 and the MRI device 510 can be mounted on different gantries, synchronized but rotating independently. In some embodiments, the radiotherapy device 520 (e.g., radiation source, detector, collimator, etc.) can be mounted relatively stationary on the main magnet of the MRI device 510, co-rotating with the main magnet.

According to the MRI equipment, the directions of the main magnetic field B0 generated by the MRI equipment and the therapeutic beam are consistent, the transverse deviation of the beam current can be reduced to the maximum extent, and the therapeutic beam can be stably accelerated to be transmitted in a stronger magnetic field. MRI devices can be designed to have a high central magnetic field strength, e.g., greater than 1.5T or more, for MRI magnetic resonance imaging.

Meanwhile, the direction of a main magnetic field B0 generated by the MRI equipment is consistent with that of the therapeutic beam, so that the phenomenon that the beam is lost due to impact on the cavity wall under the influence of the main magnetic field on an acceleration or transmission path can be avoided or reduced, and the dose rate of the radiotherapy equipment guided by magnetic resonance is improved; in addition, the therapeutic beam can reach the isocenter area of the accommodating space of the MRI equipment with higher transmission efficiency, and the design and processing difficulty of magnetic shielding of the magnet is reduced, so that the uniformity of the magnetic field of the magnet is ensured.

Fig. 9 is an illustrative medical device according to some embodiments of the present application. The medical apparatus may include an MRI apparatus 600. In some embodiments, the MRI apparatus 200 described in fig. 2 may be applied to the MRI apparatus 600. The X, Y, and Z directions in fig. 9 correspond to the X, Y, and Z directions in fig. 2.

As shown in fig. 9, MRI device 600 may include a main magnet 608. The main magnet 608 forms an accommodating space 602 extending in an axial direction (e.g., a Z direction shown in fig. 9) for accommodating the target object 607.MRI apparatus 600 may further include a patient bed 613. In some embodiments, at least a portion of the patient bed 613 may be moved in the Z-direction and into the receiving space 602 of the MRI apparatus 600. A target object 607 may be placed on the patient bed 613 and brought into the receiving space 602.

The main magnet 608 may include a first set 609 of main magnetic field coils and a second set 610 of main magnetic field coils oppositely disposed along a radial direction of the receiving space 602. The volume 602 is located between a first main magnetic field coil set 609 and a second main magnetic field coil set 610. The first 609 and/or the second 610 main magnetic field coil sets may include at least one main magnetic field coil having a three-dimensional shape that is not in the same plane, for example, a saddle-type coil, or a cos-theta type coil. For example, as shown in fig. 9, the first main magnetic field coil set 609 and the second main magnetic field coil set 610 include saddle coils.

As shown in fig. 9, the MRI apparatus 600 may comprise at least one first bore 601, through which first bore 601 a treatment beam emitted by a radiation source 606 of the radiotherapy apparatus may be directed towards at least a portion of a region of interest of the target object 607 located in the receiving space 602. Set up the through-hole on MRI equipment 600's main magnet 608, can increase the mechanical structure intensity of magnet, improve the stability of magnet, can install radiotherapy equipment's radiation source 606 above the through-hole, the higher particle transmission efficiency can be kept to trompil department, makes reaching isocenter target area that therapeutic beam does not block, improves the ray utilization ratio, finally improves the dose rate.

In some embodiments, MRI apparatus 600 may include at least one second opening 603, the at least one first opening 601 and the at least one second opening 603 being diametrically opposed along receiving space 602, and a treatment beam of the radiotherapy apparatus may be received by a detector of the radiotherapy apparatus through second opening 603. For example, the first opening 601 and the second opening 603 may be provided on the vacuum vessel to be opposite to each other in a radial direction of the accommodating space 602.

In some embodiments, the first aperture and/or the second aperture may be any shape, such as, but not limited to, circular, oval, rectangular, etc.

In some embodiments, the first aperture 601 may open between two coils of the first set of main magnetic field coils or in an area enclosed by one coil of the first set of main magnetic field coils. In some embodiments, the first aperture may open on a side of the first set of main magnetic field coils that is radially away from the target object 607 in the accommodating space 602 (as shown in fig. 9, the first aperture 601 opens on a side of the first set of main magnetic field coils 609 that is radially away from the target object 607 in the accommodating space 602). In some embodiments, the second opening may open between two coils of the second set of main magnetic field coils or in an area enclosed by one coil of the second set of main magnetic field coils. In some embodiments, the second opening may open on a side of the second set of main magnetic field coils that is radially away from the target object 607 along the receiving space 602 (as shown in fig. 9, the second opening 603 opens on a side of the second set of main magnetic field coils 610 that is radially away from the target object 607 along the receiving space 602).

In some embodiments, when MRI apparatus 600 includes at least two first apertures, the at least two first apertures may be juxtaposed in an axial direction of accommodation space 602 or a circumferential direction of accommodation space 602. A radiation source 606 of the radiotherapy apparatus may be mounted above one of the first openings. In some embodiments, when MRI apparatus 600 includes at least two second apertures, the at least two second apertures may be juxtaposed in an axial direction of accommodation space 602 or a circumferential direction of accommodation space 602. A detector of the radiotherapy apparatus may be mounted at one of the second openings. In some embodiments, the number of first and second apertures may be the same or different.

In some embodiments, the MRI device 600 may further include a gantry 605 for supporting a main magnet 608. The main magnet 608 is rotatable relative to the gantry 605. The main magnet 608 may be mounted to the housing 605 and relative rotation between the main magnet 608 and the housing 605 may be achieved, for example, by bearings.

In some embodiments, the radiotherapy device (e.g., radiation source 606, detector, collimator, etc.) and the main magnet 608 can both be mounted on the gantry 605 for common rotation.

In some embodiments, the radiotherapy device (e.g., radiation source 606, detector, collimator, etc.) may be mounted on a radiotherapy gantry other than gantry 605, rotating synchronously with, but independently of, the main magnet 608. For example, the radiotherapy gantry can have an annular shape disposed around the main magnet 608. The radiation source 606, detectors, and collimators may be mounted on the circumference of the radiotherapy gantry. As another example, a radiotherapy gantry may be located on the back of the MRI apparatus 600. The radiation source 606 may be mounted on a radiation therapy gantry via a treatment arm.

In some embodiments, the main magnet 608 may be fixed relative to the gantry 605 or the radiotherapy gantry by a suspension device.

In some embodiments, the radiotherapy device (e.g., radiation source 606, detector, collimator, etc.) can be mounted relatively stationary on the main magnet 608. For example, the radiation source 606 and/or collimator may be mounted at the first bore 601 for co-rotation with the main magnet 608. Also for example, a detector (not shown in fig. 9) can be mounted at the second bore 603 for co-rotation with the main magnet 608.

In some embodiments, the MRI apparatus 600 may further comprise at least one cooling device 604 for cooling the superconducting coils of the main magnet. In some embodiments, the cooling of the superconducting coils may include liquid helium immersion cooling, an external vacuum vessel and an internal thermal shield for connecting the cryovessel of the MRI apparatus 600, and may also be used to secure the main magnet 608 to an external support structure (e.g., the gantry 605). In some embodiments, if the MRI device 600 rotates with the radiation therapy device, the main magnet structure can take some acceleration load when the system starts, stops, especially when the safety interlock trigger system requires a sudden stop. The suspension device can adopt a titanium alloy pull rod, so that the main magnet can bear various motion working conditions. In some embodiments, the suspension may be provided with temperature nodes or be segmented to reduce heat leakage from the magnets.

FIG. 10 is a schematic diagram illustrating an exemplary conduction cooling approach according to some embodiments of the present application.

In some embodiments, the main magnet may be a superconducting magnet, and the superconducting magnet may be cooled by conduction, that is, a coil of the superconducting magnet is directly connected to the refrigerator cold head through a cold conduction structure, so as to achieve cooling of the magnet.

As shown in fig. 10, a superconducting magnet 702 may be arranged in the vacuum vessel 701. There may be a shielding layer 703 between the superconducting magnet 702 and the vacuum vessel 701 to reduce radiative heat transfer. The shield 703 may be connected to a refrigerator primary cold head end plate 704. The superconducting magnet 702 may be connected to a refrigerator secondary coldhead end plate 705 by a cold conduction structure 706.

Compared with a liquid helium immersion cooling method, a certain temperature difference may exist in structures such as a coil and a magnet frame for supporting the coil. In order to improve the reliability of the superconducting magnet and reduce the heat transfer temperature difference, the superconducting magnet can adopt high-thermal conductivity aluminum alloy as an inner framework and be bound with high-purity oxygen-free copper or high-purity aluminum to form a temperature equalizing structure. And the contact interface is pressed by indium foil, so that the contact thermal resistance is improved.

Compared with a liquid helium soaking cooling mode, the liquid helium consumption is less in a conduction cooling mode, and the operation cost is lower; in addition, the conduction cooling mode does not need liquid helium to soak the superconducting coil, and the superconducting coil is prevented from being easily quenched due to the change of the liquid level of the liquid helium caused by the rotation of the main magnet.

The above description is intended to be illustrative, and not to limit the scope of the application. Many alternatives, modifications, and variations will be 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 radiotherapy device in the present application may be replaced by a CT device or an X-ray device, the MRI device in the present application may constitute a multi-modality imaging apparatus together with the CT device or the X-ray device, and the MRI device may rotate synchronously with the CT device or the X-ray device, so that the axial direction of the beam emitted by the radiation source is the same as the direction of the main magnetic field. However, such changes and modifications do not depart from the scope of the present application.

The beneficial effects that may be brought by the embodiments of the present description include, but are not limited to: (1) Compared with the runway-type coil, the projected area of the coil with the three-dimensional shape which is not in the same plane along the main magnetic field direction is smaller than that of the runway-type coil, and a stronger magnetic field or a magnetic field with a larger shimming area can be generated; on the other hand, if it is desired to generate magnetic fields of the same strength or the same shim area, the required coils with three-dimensional shapes that are not in the same plane will have a smaller mass than the racetrack coils, which makes the MRI apparatus more portable; (2) The sides of the coil having the three-dimensional shape not in the same plane are closer to the central region of the accommodation space than the racetrack-type coil, and therefore the contribution of the coil having the three-dimensional shape not in the same plane to the central field is higher; (3) According to the MRI equipment, the directions of the main magnetic field B0 generated by the MRI equipment and the therapeutic beam of the radiotherapy equipment are consistent, the transverse deviation of the beam current can be reduced to the maximum extent, and the therapeutic beam can be stably accelerated and transmitted in a stronger magnetic field. MRI devices can be designed to have a high central magnetic field strength, e.g., greater than 1.5T or more, for MRI magnetic resonance imaging; (4) The direction of a main magnetic field B0 generated by the MRI equipment is consistent with that of the therapeutic beam, so that the beam current can be prevented or reduced from impacting the cavity wall and losing under the influence of the main magnetic field on an acceleration or transmission path, and the dosage rate of the radiotherapy equipment guided by magnetic resonance is improved; the therapeutic beam can reach the isocenter area of the accommodating space of the MRI equipment with higher transmission efficiency, and the design and processing difficulty of magnetic shielding of the magnet is reduced, so that the magnetic field uniformity of the magnet is ensured.

Having thus described the basic concept, it will be apparent to those skilled in the art from this disclosure that the foregoing disclosure is by way of example only, and is not intended to limit the present application. Various modifications, improvements and adaptations of the present application may occur to those skilled in the art, although they are not explicitly described herein. Such alterations, modifications, and improvements are intended to be suggested herein and are intended to be within the spirit and scope of the exemplary embodiments of the present application.

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

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

Claims

1. A medical system, comprising:

a vacuum container (701) that surrounds and forms an accommodation space (602) extending in the axial direction;

a main magnet (608) disposed within the vacuum vessel (701), the main magnet (608) including a first set of main magnetic field coils (609) and a second set of main magnetic field coils (610), and the first set of main magnetic field coils (609) and the second set of main magnetic field coils (610) being oppositely disposed on both sides of the accommodating space (602);

a radiation source (606) arranged outside the vacuum vessel (701), and a projection of the radiation source (606) in a radial direction of the receiving space at least partly falls within an area enclosed by the first set of main magnetic field coils (609) or within an area enclosed by the second set of main magnetic field coils (610).

2. The medical system according to claim 1, characterized in that the first (609) or second (610) set of main magnetic field coils comprises a plurality of main magnetic field coils.

3. The medical system of claim 2, wherein a plurality of the main magnetic field coils are arranged side-by-side along the axial direction.

4. The medical system of claim 2, wherein a plurality of the main magnetic field coils are arranged in a nested arrangement.

5. The medical system of claim 2, wherein the main magnetic field coil comprises at least one of a saddle coil, a cos-theta coil, a racetrack coil.

6. The medical system according to claim 1, wherein the vacuum container (701) is opened with a first opening (601), the radiation source (606) is mounted on the first opening (601), and the radiation source (606) and the vacuum container (701) can rotate synchronously.

7. The medical system according to claim 6, further comprising a probe, wherein the vacuum container (701) is opened with a second opening (603), the probe is mounted in the second opening (603), and the first opening (601) and the second opening (603) are oppositely arranged at two sides of the accommodating space (602).

8. The medical system according to claim 6, further comprising a gantry (605), the vacuum vessel (701) being mounted to the gantry (605) such that the vacuum vessel (701) is rotatable relative to the gantry (605) about an axial direction of the receiving space (602).

9. The medical system of claim 1, further comprising at least two gantries (605), wherein one gantry (605) is configured to hold the radiation source (606) and another gantry is configured to hold the vacuum vessel (701).

10. The medical system according to any of claims 1-9, characterized in that the main magnet (608) further comprises a first set of shielding coils (903) and a second set of shielding coils (904), and that the first set of shielding coils (903) is arranged inside the vacuum vessel (701) outside the first set of main magnetic field coils (609); the second set of shield coils (904) is arranged inside the vacuum vessel (701) outside the second set of main magnetic field coils (610).