Mri system and receive coil arrangement

Abstract

An MRI system receive coil device (3) for use with a host MRI scanner device. The device comprises: at least one primary receive coil (6) having a first impedance at a predetermined frequency and a first dimension defined by a cross-sectional area bounded by the primary receive coil; and, at least one secondary receive coil (7) having a second impedance at the predetermined frequency and a second dimension defined by a cross-sectional area bounded by the secondary receive coil, wherein the first impedance is lower than the second impedance and the first dimension is greater than the second dimension.

Description

Technical Field

[0001] The present invention relates to an MRI system including a receiving coil device, and to a receiving coil device for use in an MRI system and in combined systems (such as MR-Linac systems and PET-MR systems) in some embodiments, wherein the combined system is used in conjunction with another system that depends on a radiation source. Background Technology

[0002] An MRI system typically includes a main MRI scanner unit, a patient support or bed on which the patient lies during the scan, and in at least some cases includes discrete, localized receiver coil units (or body part-specific receiver coils) arranged in the region of the specific body part to be scanned.

[0003] The main MRI scanner unit typically includes a main magnet, gradient coils, RF transmitting coils, and receiving coils, all arranged in a main unit with a bore in which the patient is positioned during the scan. Where body-site-specific receiving coils are present, these coils are also typically positioned within the bore during the scan.

[0004] As is well known, MRI (Magnetic Resonance Imaging) systems are widely used for imaging subjects and can also be used in combined systems such as MR-Linac and PET-MR. These combine MRI with other radiation-using techniques, for example, for treatment in MR-Linac or for providing functional imaging in PET-MR. In MRI operation, a magnet creates a large static magnetic field B0, and an RF transmitting coil generates an alternating magnetic field B1. Whether the receiving coil is located in the main unit or in a body site-specific receiving coil, the receiving coil is arranged to collect magnetic resonance signals (i.e., acquire magnetic resonance data). Gradient coils are used to allow spatial encoding in the B0 field to achieve tomographic imaging.

[0005] When an MRI system is operated using only the receiving coil located in the main unit of the scanning device, the resolution and accuracy of the results can be limited in some cases. This leads to the use of discrete, arguably localized receiving coils, such as the body part-specific coils mentioned above, in order to improve imaging of selected locations / body parts.

[0006] However, existing body part-specific receiver coil devices have limitations. These include the possibility that positioning the receiver coil device around or within a specific body part can be cumbersome, and / or that the receiver coil device may provide insufficient imaging results for the region of interest, and / or that the receiver coil device may be incompatible with other systems, such as systems that use radiation sources, such as linear accelerators or positron emission tomography systems. Summary of the Invention

[0007] Therefore, it is desirable to provide an MRI system receiving coil device designed to address at least one of these problems, as well as an MRI system and combination therapy and / or imaging system including such an MRI system receiving coil device.

[0008] According to a first aspect of the invention, an MRI system receiving coil device is provided for use with a main MRI scanner device and includes: at least one main receiving coil having a first impedance at a predetermined frequency and a first dimension defined by a cross-sectional region bounded by the main receiving coil; and at least one auxiliary receiving coil having a second impedance at the predetermined frequency and a second dimension defined by a cross-sectional region bounded by the auxiliary receiving coil, wherein the first impedance is lower than the second impedance and the first dimension is greater than the second dimension.

[0009] This allows for a coil arrangement in which the main receiving coil helps to obtain signals from relatively deep regions of the object to be imaged (although still local to the receiving coil arrangement), while the auxiliary receiving coil helps to obtain signals from regions relatively close to the auxiliary receiving coil.

[0010] Preferably, the receiving coil device includes a plurality of auxiliary receiving coils, each auxiliary receiving coil having an impedance higher than the first impedance at the predetermined frequency, and each auxiliary receiving coil having a size smaller than the first size defined by a cross-sectional area bounded by the respective auxiliary receiving coil.

[0011] Because these auxiliary receiving coils have relatively high impedance, the problem of mutual coupling between the coils and their surrounding environment will be reduced.

[0012] While providing one primary receiving coil is generally preferred, in some embodiments, the receiving coil assembly includes multiple primary receiving coils. In this case, the multiple primary receiving coils are typically kept in a precise positional relationship with each other to minimize mutual coupling—for example, the multiple primary receiving coils may be mounted on a rigid support.

[0013] The receiving coil device can be a body part-specific receiving coil device arranged for use in imaging a predetermined part of an object.

[0014] The receiving coil device may include a support structure on which at least one of the main receiving coil and the auxiliary coil is carried.

[0015] The support structure can maintain at least one of the main receiving coil and the auxiliary coil in the desired shape.

[0016] The support structure may include a positioning device for holding at least one of the main receiving coil and the auxiliary coil in a desired shape.

[0017] The positioning device may include a fastening device. The positioning device may include one or more grooves or channels.

[0018] The support structure may include at least two parts, wherein the first part carries the main receiving coil and the second part carries the auxiliary receiving coil.

[0019] The at least two portions of the support structure are arranged to be movable between an access configuration and an operational configuration, the access configuration allowing an object to be positioned between the two portions of the support structure, and the operational configuration for positioning the main receiving coil and the auxiliary receiving coil relative to each other in desired locations for use during imaging operation of an MRI machine with which the receiving coil assembly is to be used.

[0020] This allows for easy inclusion of a portion of the object into the receiving coil assembly and / or easy mounting of the receiving coil assembly onto the object, while allowing for proper positioning of the coil relative to the object for imaging.

[0021] At least one auxiliary receiving coil can be more flexible than the main receiving coil.

[0022] This facilitates the mounting of at least one auxiliary receiving coil to the corresponding support portion. It also allows for the use of a relatively flexible support portion to support at least one auxiliary receiving coil.

[0023] The support portion supporting at least one auxiliary receiving coil can be more flexible than the support portion supporting the main receiving coil.

[0024] One of the at least two support components may include a base portion for resting on or being attached to a patient support bed for use with an MRI machine.

[0025] Another of the at least two support portions may include a cover portion for mounting on the base portion. A hook-and-loop fastening device may be provided to secure the cover portion to the base portion.

[0026] The base portion can support the main receiving coil. The cover portion can support the auxiliary receiving coil. Preferably, there are multiple auxiliary receiving coils, each of which is supported by the cover portion.

[0027] The cover portion may include a plastic material base supporting at least one auxiliary receiving coil and a foam material layer covering at least one auxiliary receiving coil.

[0028] The cover portion may include at least one fastening device for holding at least one auxiliary receiving coil in place on the substrate. The fastening device may include threads. At least one auxiliary receiving coil may be screwed into place.

[0029] The cover portion may include multiple cover portions, each cover portion being used to cover a corresponding portion of interest in the object, and at least one of the multiple auxiliary receiving coils is disposed on the corresponding cover portion of the multiple cover portions.

[0030] The receiving coil device can be a head and / or face and / or neck and / or shoulder receiving coil device.

[0031] The base portion may include at least a portion of a pillow portion for supporting the head of the object. The cover portion may be arranged and positioned above the head and / or face and / or neck and / or shoulders of the object. The cover portion may have at least one of a head cover portion, a face cover portion, a neck cover portion, and a shoulder cover portion.

[0032] At least one of the plurality of auxiliary receiving coils may be disposed on the face covering portion, and / or at least one of the plurality of auxiliary receiving coils may be disposed on the neck covering portion, and / or at least one of the plurality of auxiliary receiving coils may be disposed on the head covering portion, and / or at least one of the plurality of auxiliary receiving coils may be disposed on the shoulder covering portion.

[0033] In one set of embodiments, the receiving coil device includes a plurality of auxiliary receiving coils, each of which is carried by a cover portion and the cover portion has a face covering portion and a neck covering portion, wherein at least one of the plurality of auxiliary receiving coils is disposed on the face covering portion and / or at least one of the plurality of auxiliary receiving coils is disposed on the neck covering portion.

[0034] In a subset of such embodiments, the cover portion may further include a head cover portion, and in this case, at least one of the plurality of auxiliary receiving coils may be disposed on the head cover portion.

[0035] In another subset of such embodiments, the cover portion may further include a shoulder cover portion, and in this case, at least one of the plurality of auxiliary receiving coils may be disposed on the shoulder cover portion.

[0036] In another set of embodiments, the receiving coil device includes a plurality of auxiliary receiving coils, each of which is carried by a cover portion and the cover portion has a face covering portion and a head covering portion, wherein at least one of the plurality of auxiliary receiving coils is disposed on the face covering portion, and / or at least one of the plurality of auxiliary receiving coils is disposed on the head covering portion.

[0037] The receiving coil device can be arranged to allow use in addition to the fixation mask or other clamps provided for radiotherapy treatment, that is, to allow use around the fixation mask or other clamps provided for radiotherapy treatment.

[0038] The cover portion can be arranged to have at least one ray-permeable portion.

[0039] The receiving coil device may include an area without electronic components, which corresponds to an area through which radiation—such as a beam of radiation therapy applied during use or radiation used to form an image—can pass during use.

[0040] The receiving coil device can be arranged in a method or system for radiotherapy in conjunction with MRI, for example, as part of an MR-Linac system.

[0041] The receiving coil device can be arranged in a method or system that has radiation-based imaging in conjunction with MRI, for example as part of a PET-MR system.

[0042] The receiving coil device may include at least one tuning capacitor for tuning at least one of the respective receiving coils.

[0043] At least one tuning capacitor may be located outside the area without electronic components.

[0044] At least one auxiliary receiving coil may include at least one section of coaxial cable.

[0045] At least one auxiliary receiving coil may include a section of coaxial cable arranged in a loop, with a gap provided in the outer conductor of the coaxial cable at a midpoint around the loop, and the outer conductor at a first end of the coaxial cable section connected to the outer conductor at a second end of the coaxial cable section.

[0046] Each end of the coaxial cable in the segment can be connected to a mating plate.

[0047] The main receiving coil may include at least one unshielded conductor portion.

[0048] The main receiving coil may include two unshielded conductor portions arranged together in a loop. A corresponding first end of each unshielded conductor portion may be connected to a mating plate, and a corresponding second end of each unshielded conductor portion may be connected to a detuning plate. A first support portion may include at least one channel or recess in which at least a portion of at least one unshielded conductor portion is received.

[0049] The first support portion may include a plate portion and a pair of upright portions protruding from the plate portion. A first portion of the main receiving coil may be supported on the plate portion, while a second and third portion of the main receiving coil may be supported on the pair of upright portions.

[0050] In one set of embodiments, the plate portion includes a plate channel in which a first portion of a main receiving coil is received, the first upright portion of the pair of upright portions includes a first upright channel in which a second portion of the main coil is received, and the second upright portion of the pair of upright portions includes a second upright channel in which a third portion of the main coil is received.

[0051] In one embodiment, the receiving coil device includes a main receiving coil and seven auxiliary receiving coils.

[0052] According to another aspect of the invention, a cover portion device is provided for use in a receiving coil device as defined above, the cover portion device comprising a plurality of auxiliary receiving coils of the receiving coil device and a cover portion for carrying and supporting each auxiliary receiving coil.

[0053] According to another aspect of the invention, an MRI system is provided, comprising a main MRI scanner assembly, a patient support, and an MRI system receiving coil assembly as defined above, disposed on the patient support and electrically connected to the main MRI scanner assembly.

[0054] The receiving coil device may include a support structure, on which at least one of a main receiving coil and an auxiliary coil is carried, and at least a portion of the support structure may be mounted on or form part of a patient support.

[0055] In one set of implementations, the support structure may include a base portion that carries the main receiving coil and may be mounted on or form part of the patient support.

[0056] According to another aspect of the present invention, an MR-Linac system is provided, comprising an MRI system as defined above and a medical linear accelerator system.

[0057] According to another aspect of the present invention, a PET-MR system is provided, comprising an MRI system as defined above and a positron emission tomography (PET) system.

[0058] Note that, generally speaking and with any necessary modifications to the wording, all further features defined above after any aspect of the invention can be used as further features of all other aspects of the invention defined above. For the sake of brevity only, these further features have not been repeated after each aspect of the invention. Attached Figure Description

[0059] Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings, in which:

[0060] Figure 1 An MRI system including a receiving coil is schematically shown;

[0061] Figure 2 This schematically shows the inclusion of Figure 1 The type of receiving coil device in the MRI system is in place on the object.

[0062] Figure 3 schematically shown Figure 2 The base plate of the receiving coil device shown;

[0063] Figure 4 schematically shown Figure 2 The cover portion of the receiving coil device shown;

[0064] Figure 5 Showing more details Figure 3 The base plate shown is a portion of which is arranged to receive the main receiving coil;

[0065] Figure 6 The main receiving coil in the base plate is shown, but part of the base plate has been removed;

[0066] Figure 7 The illustration shows examples including Figure 2 The connection arrangement of the auxiliary receiving coil in the receiving coil device shown;

[0067] Figure 8A and Figure 8B The following are examples of positioning around an object. Figure 2 A schematic diagram of the main coil and auxiliary coil of the receiving coil device, including front and side views; and

[0068] Figure 9 It shows Figure 2 The diagram shows the connections between the various components in the receiving coil device. Detailed Implementation

[0069] Figure 1An MRI system is shown, comprising: a main scanner unit 1; a patient support 2 arranged to support a patient when the patient is located in the scanner unit 1; and an MRI system receiving coil unit 3, which is separate from the main scanner unit and, in this embodiment, is a body site-specific receiving coil unit. More generally, such a receiving coil unit 3 may be referred to as a local receiving coil unit.

[0070] As mentioned above, in some cases, the MRI system will be used in combination with other systems to provide, for example, an MR-Linac system, which includes an MRI system and a medical linear accelerator system; or, in another embodiment, a PET-MR system is provided, which includes an MRI system and a positron emission tomography (PET) system. In this case, Figure 1 The MRI system shown can be supplemented by... Figure 1 The linear accelerator system or positron emission tomography system S is shown only in a highly schematic form and illustrated by dashed lines.

[0071] The main MRI scanner unit 1 can be a completely conventional main MRI scanner unit, including a main magnet 11 (typically a superconducting electromagnet), an RF transmitting coil 12, a gradient coil 13, and a main unit receiving coil 14. These components are housed in a body of the MRI scanner unit 1 having a main aperture B, in which a patient support 2 is disposed, or more typically, the patient support 2 can carry the patient into the main aperture B until the operating position is reached.

[0072] At least during use, a body part-specific receiving coil device 3 is also disposed in this main aperture B. Where applicable, at least a portion of a medical linear accelerator system or positron emission tomography (PET) system S may also be located in said main aperture B during operation.

[0073] In addition to being located in the main port B of the main MRI scanner 1 during operation, the receiving coil device 3 is electrically connected to the main scanner device 1 so that the magnetic resonance signal picked up by the receiving coil device 3 can be fed into the main scanner device 1 for processing.

[0074] When processing and generating images, the signal picked up by the receiving coil device 3 can be used alone or in combination with the signal picked up by the main unit receiving coil 14. In some cases, the main MRI scanner device 1, which does not have its own main unit receiving coil 14, can be used with the receiving coil device 3 of the present type.

[0075] The structure and operation of the MRI scanner device are well developed and understood, and the current idea relates to the receiving coil device 3 used with such an MRI scanner device. Therefore, further description of the structure and operation of the MRI scanner device 1 is unnecessary, and the remainder of this description relates to the receiving coil device 3.

[0076] Figure 2 A body part-specific receiving coil device 3 is shown schematically in more detail. The body part-specific receiving coil device 3 includes a cover portion 4 and a base portion 5. The base portion 5 is arranged to rest on the patient support 2, or in some embodiments may be made as an integral part of the patient support 2. Conversely, the cover portion 4 is removably mounted on the base portion 5 so that it can be mounted over an object and then secured in place on the base portion 5.

[0077] If by consideration Figure 3 , Figure 4 , Figure 5 and Figure 6 It can be seen that the body-specific receiving coil device 3 includes a main receiving coil 6 (see...). Figure 5 and Figure 6 ) and multiple auxiliary receiving coils 7 (see Figure 4 The base portion 5 is arranged to support the main receiving coil 6 and the cover portion 4 is arranged to support the auxiliary receiving coil 7.

[0078] The base portion 5 includes a plate portion 51 and two upright portions 52. The upright portions 52 can be, for example... Figure 3 and Figure 5 As seen in the image, the plate portion 51 has two layers, 51a and 51b. The upright portion 52 is supported on the upper layer 51a, as shown in the image. Figure 3 and Figure 5 As can be seen in. Figure 6 In the middle, the upper layer 51a is raised to show the lower layer 51b and to better show the main receiving coil 6.

[0079] The base portion 5 is provided with multiple channels 52a and 52b for supporting the main receiving coil 6 and holding it in a predetermined position. A corresponding channel 52a (as shown in the attached diagram) is provided in each upright portion 52. Figure 5 Only one channel can be seen in the middle), which is used to hold the corresponding part of the main receiving coil 6 in place in the upright part 52.

[0080] By considering together, for example Figure 2 , Figure 3 , Figure 4 and Figure 5It is understood that, in use, this portion of the main receiving coil 6 will be very close to the object, particularly the head of the object in the specific embodiment shown. The specific shape and path of the coil 6 are chosen to give the desired receiving characteristics, such as maximizing the penetration depth and ensuring a relatively constant electromagnetic coupling of energy to the object's tissue.

[0081] The lower layer 51b of the board portion 51 includes corresponding channels 52b for holding other parts of the main receiving coil 6 in place.

[0082] The main receiving coil 6 comprises multiple unshielded conductor segments. In this embodiment, two sections of unshielded conductor 61 are provided. A first unshielded conductor extends in a channel 52a of a first post 52, and a second unshielded conductor extends in a channel 52a of another post 52. First ends of these conductor segments 61 are connected to a detuning plate 62, while other corresponding ends of the two conductor segments 61 are connected to a matching plate 63. The detuning plate 62 and the matching plate 63 each include at least one electronic component, such as at least one tuning capacitor in the case of the matching plate 63.

[0083] like Figure 6 As seen, the detuning plate 62 and the matching plate 63 are positioned outside the central region of the coil 6, i.e., away from the location of the upright portion 52 and those portions of the coil 6 that will be closest to the part of interest in the object. This creates an electronically free region in the area of ​​interest of the object. This is particularly interesting when the body-specific receiving coil device 3 is used in a combined system of the type described above, where radiation is used in the combined system. Radiation can pass through this central region, i.e., the area of ​​interest in the object, without being adversely affected by the presence of electrical components and / or without the risk of damaging those electrical components. Therefore, this arrangement of the main receiving coil 6 facilitates the use of this receiving coil device in systems such as PET-MR and MR-Linac systems.

[0084] The base portion 5, namely the plate portion 51 and the upright portion 52, is made of a relatively rigid plastic material and is used to hold the main receiving coil 6 in a predetermined position.

[0085] As mentioned above, this is important because changes to the shape of the main receiving coil 6 will tend to affect tuning and matching, which will adversely affect the sensitivity of the main receiving coil 6. The rigid structure and the shape and positioning of the coil 6 were chosen to minimize these effects.

[0086] Each auxiliary receiving coil 7 has a different structure than the main receiving coil 6. While the main receiving coil 6 is made of unshielded conductor and has relatively low impedance, the auxiliary receiving coils 7 are arranged as high-impedance coils. In particular, these coils 7 have a higher impedance than the main receiving coil 6. Furthermore, the auxiliary receiving coils 7 are smaller in size than the main receiving coil 6, especially the region bounded by the auxiliary receiving coils 7 is smaller than the region bounded by the main receiving coil 6. This means that the main receiving coil 6 is more suitable for receiving signals emitted from deep within the object, while the auxiliary receiving coils 7 are more suitable for picking up signals emitted from the region of the object close to the auxiliary receiving coil 7 itself.

[0087] Furthermore, due to the high-impedance nature of the auxiliary receiving coils 7, they are much less coupled to the environment, so precise positioning is not so critical. This leads to the possibility of positioning these auxiliary receiving coils 7 more accurately relative to the object and allowing them to conform to the shape necessary to bring them into close contact with the relevant areas of interest in the object.

[0088] Figure 7 The connection arrangement of each auxiliary receiving coil 7 is schematically shown. Each auxiliary receiving coil 7 is made of a section of coaxial cable including a center conductor 71 and an outer shielding conductor 72. In the receiving coil, the center conductor 71 is continuous around the coil, and the end of the center conductor 71 is connected to a corresponding matching plate 73 (see...). Figure 4 On the other hand, the shielding conductor 72 has a gap at its end away from the inner conductor 71, while the two ends of the shielding conductor 72 near the inner conductor 71 are connected together. Each of the matching plates 73 includes at least one electronic component, such as at least one tuning capacitor.

[0089] Due to the characteristics of the high-impedance coil, the total length of each coaxial cable of the coil is limited to nearly half a wavelength, thus limiting the overall size of the auxiliary receiving coil 7.

[0090] Each of these auxiliary receiving coils 7 is supported by a plastic base 41 of the cover portion 4. The auxiliary receiving coils 7 can be held in place by stitching—for example, using textile yarn. In this embodiment, the base 41 is made of a relatively flexible plastic material, and overall, the base 41 and the cover portion 4 are much more flexible than the base portion 5. Because the base 41 is flexible, the auxiliary coils 7 are flexible, and when in the desired position, the auxiliary coils 7 can operate effectively, meaning that the cover portion 4 can be designed to fit snugly against the area of ​​interest.

[0091] Therefore, in this embodiment, the cover portion 4 is arranged to be positioned on the patient's head, face and neck, and accordingly includes a cover portion for covering the subject's head, face and neck when in place.

[0092] The combination of cover part 4 and auxiliary coil 7 can be referred to as cover part device 4, 7. The combination of base part 5 and main coil 6 can be referred to as base part device 5, 6.

[0093] When the object is positioned on the base portion 5 and the cover portion 4 is in place, the positions of the main coil 6 and the auxiliary coil 7 relative to the object can be... Figure 8A and Figure 8B This is best seen in the middle.

[0094] In this configuration, the main coil 6 can be seen located in the area of ​​the patient's head. The main coil 6 is better positioned to acquire data from deeper within the object. The receiving coil 6 can effectively pick up signals generated from any area within the patient's head and neck.

[0095] On the other hand, the auxiliary coils 7 are located at different positions above the patient's face and neck. There is partial overlap between each auxiliary coil 7, but primarily each auxiliary coil 7 aims to pick up signals from different areas of the subject's face and neck. In this embodiment, there are seven auxiliary coils 7, three of which are arranged for positioning above the subject's face, and four of which are arranged for positioning above the subject's neck and shoulders. Accordingly, if the cover portion 4 is considered as, for example... Figure 4 As illustrated, four auxiliary coils 7 are provided on the neck covering portion of the cover, and three auxiliary coils 7 are provided on the face covering portion of the cover 4.

[0096] In this embodiment, the auxiliary coils 7 are arranged to overlap each other by 10-15% to further reduce residual inductive coupling.

[0097] Furthermore, the matching plate 73 for the auxiliary coil 7 is kept outside the central region, i.e. the region of interest in the object, so that there is an electronically free area that provides the benefits described above.

[0098] In practice, the base 41, auxiliary coil 7, and matching plate 73 of the cover portion devices 4 and 7 will be covered with a foam layer disposed on each side of the base 41. In this embodiment, the cover portion 4 is arranged to be held in place on the base portion 5 using hook and loop fasteners 44 disposed at appropriate attachment positions.

[0099] Note that the flexible design of the cover 4 and the fact that the auxiliary coil 7 can be positioned in different locations and bent into slightly different shapes facilitate the provision of cover portion devices 4, 7 that can be used above masks or other clamps required for use in combined systems. For example, in an MR-Linac system in which a patient-specific fixation mask or clamp is provided to properly guide radiation used in radiotherapy delivered by the MR-Linac system, this cover portion 4 can be used in conjunction with an existing mask or clamp without modification.

[0100] Figure 9 It shows Figure 2 Figure 8 shows a schematic diagram of the overall connection arrangement of the receiving coil assembly. The low-impedance main coil 6 and the high-impedance auxiliary coil 7 are connected to the preamplifier board 9 via appropriate cable traps 8. Their outputs are fed to the driver fault board 10, and their outputs as a whole become the output of the receiving coil assembly 3, which is then fed to the main MRI scanner assembly 1.

Claims

1. An MRI system receiving coil device for use with a main MRI scanner device and comprising: At least one main receiving coil, the at least one main receiving coil having a first impedance at a predetermined frequency and a first dimension defined by a cross-sectional area limited by the main receiving coil; And at least one auxiliary receiving coil, the at least one auxiliary receiving coil having a second impedance at the predetermined frequency and a second dimension defined by a cross-sectional region limited by the auxiliary receiving coil, wherein the first impedance is lower than the second impedance and the first dimension is larger than the second dimension; The at least one auxiliary receiving coil includes at least one section of coaxial cable, the main receiving coil includes at least one unshielded conductor portion, and the at least one auxiliary receiving coil is more flexible than the main receiving coil; The MRI system receiving coil device further includes a support structure on which the at least one main receiving coil and the at least one auxiliary receiving coil are carried. The support structure comprises at least two parts, wherein a first part of the at least two parts carries the main receiving coil, and a second part of the at least two parts carries the auxiliary receiving coil; as well as The first of the at least two portions includes a base portion for resting on or being attached to a patient support bed of an MRI machine, and the second of the at least two portions includes a cover portion for mounting on the base portion.

2. The MRI system receiving coil device according to claim 1, wherein the receiving coil device comprises a plurality of auxiliary receiving coils, each auxiliary receiving coil having an impedance higher than the first impedance at the predetermined frequency, and each auxiliary receiving coil having a size smaller than the first size defined by a cross-sectional area bounded by the respective auxiliary receiving coil.

3. The MRI system receiving coil assembly of claim 1, wherein at least two portions of the support structure are arranged to be movable between an access configuration and an operational configuration, the access configuration allowing an object to be positioned between the two portions of the support structure, and the operational configuration for positioning the primary receiving coil and the auxiliary receiving coil relative to each other in desired positions for use during imaging operation of an MRI machine with which the receiving coil assembly is used.

4. The MRI system receiving coil device according to claim 3, wherein the support portion supporting the at least one auxiliary receiving coil is more flexible than the support portion supporting the main receiving coil.

5. The MRI system receiving coil device according to claim 1, wherein the cover portion includes a plurality of covering portions, each covering portion for covering a corresponding portion of interest in the object, a plurality of auxiliary receiving coils are present and at least one of the plurality of auxiliary receiving coils is disposed on a corresponding covering portion of the plurality of covering portions.

6. The MRI system receiving coil device of claim 1, wherein the base portion includes at least a portion of a pillow portion for supporting the head of the subject.

7. The MRI system receiving coil device according to claim 1, wherein the receiving coil device is a head and / or face and / or neck and / or shoulder receiving coil device.

8. The MRI system receiving coil device of claim 1, wherein the receiving coil device is arranged to allow use in addition to a fixation mask or other clamp provided for radiotherapy treatment, i.e., to allow use around a fixation mask or other clamp provided for radiotherapy treatment.

9. The MRI system receiving coil device according to claim 1, wherein the receiving coil device includes an electronic component-free region corresponding to an area through which radiation can pass during use.

10. The MRI system receiving coil device of claim 9, wherein the area without electronic components corresponds to the area through which the radiotherapy beam applied during use or the radiation used in forming an image can pass.

11. The MRI system receiving coil device of claim 1, wherein the at least one auxiliary receiving coil comprises a section of coaxial cable arranged in a loop, a gap being provided in the outer conductor of the coaxial cable at a midpoint around the loop, and the outer conductor at a first end of the section of the coaxial cable is connected to the outer conductor at a second end of the section of the coaxial cable.

12. An MRI system comprising a main MRI scanner assembly, a patient support, and an MRI system receiving coil assembly according to any one of claims 1 to 11, the MRI system receiving coil assembly being disposed on the patient support and electrically connected to the main MRI scanner assembly.

13. An MR-Linac system comprising the MRI system and medical linear accelerator system according to claim 12.

14. A PET-MR system comprising the MRI system and positron emission tomography system according to claim 12.

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