3D printed MRI coils, phantoms, and shimming elements

Abstract

The present invention relates to a configuration for MRI or NMR measurements comprising one or more 3D printed hollow elements adapted to the shape of the object to be measured, characterized in that in one or more of the 3D printed elements the walls of the element are made from a UV-curable, electrically non-conductive material forming one or more channels, and in at least one of the elements having said walls the channel is composed of at least two material plugs of at least two different immiscible materials selected from the group consisting of dielectric materials, electrically conductive materials and materials with high electrical resistance.

Description

Technical Field

[0001] The present invention relates to electronic circuits suitable for use in NMR / MRI / MRS and other MR-related applications fabricated by additive manufacturing.

Background Art

[0002] The use of nuclear magnetic resonance (NMR) / magnetic resonance imaging (MRI) / magnetic resonance spectroscopy (MRS) scanners is restricted by (i) the lack of homogeneity of the RF field and the B0 field, and (ii) an insufficient signal-to-noise ratio (SNR).

[0003] Assuming x is the distance from the surface coil, the SNR scales as 1 / x 3 so it is very important to place the surface coil as close as possible to the subject. The high cost of such subject-specific RF coils hinders the design suitable for clinical applications.

[0004] Screen-printed coils have offered the most promising advance in overcoming this problem. Screen-printed coils are semi-flexible and therefore can more easily conform to the patient's shape. A closer fit to the subject increases the signal-to-noise ratio (SNR) while simultaneously enabling imaging of a wider range of patient sizes and shapes. The manufacturing of coils by screen printing is complex. Screen-printed paste is extruded onto a flexible substrate by moving a squeegee across the screen. Each printed layer is then dried in an oven. After post-processing, electronic components are soldered onto the screen-printed coil to complete the electronic circuit. These discrete components consist of inductors, capacitors, and resistors necessary for the efficient tuning / matching / detuning and decoupling of the electronic circuit, ensuring efficient energy transfer of the coil. Finally, the flexible substrate on which the coil is printed can be bent around the body part being imaged.

[0005] Because screen-printed coils are 2D prints wrapped around arbitrarily complex 3D objects, they lack the ability to produce NMR / MRI coils that are sufficiently conformal to the patient. Furthermore, manual soldering of electronic components onto screen-printed coils requires high-precision manual work, resulting in poor time efficiency and high overall coil costs.

[0006] As an alternative, Non-Patent Document 1 proposes 3D printing MR probe heads by printing channels using stereolithography and then continuously filling these channels with liquid metal. While this method offers greater flexibility in probe head design, it still fails to overcome the problem of integrating the electronic components required for efficient use of the probe head, particularly when targeting more complex coils for MRI applications.

[0007] Non-patent documents 2 and 3 disclose a 3D printed NMR / MRI coil comprising a conductive printed element and a capacitive printed element.

[0008] B0 heterogeneity is often induced by the subject itself. Since each patient's anatomical tissue differs, the induced heterogeneity also differs. Passive shimming and / or active shimming can be applied to eliminate these unwanted heterogeneities. Current passive shimming techniques are cumbersome as they require the repetitive manual placement of paramagnetic, diamagnetic, or ferromagnetic elements. Active shimming requires less manual work as a variable current is induced through a specialized coil to generate an opposing magnetic field. Current active shimming techniques primarily focus on canceling only the low-harmonic components of the heterogeneous field, and therefore cannot cancel complex B0 distortions. This is due to the difficulty and high cost of manufacturing active shimming coils specifically tailored to fit a particular subject. [Prior art documents] [Non-patent literature]

[0009] [Non-Patent Document 1] Xie et al. (2020) Nat Commun 11, 5793 [Non-Patent Document 2] Corea et al. (2016) 7:10839 [Non-Patent Document 3] Horch & Gore (2017) Magn Reson Imaging S0730-725X(17)30004-8 [Overview of the project]

[0010] This invention discloses 3D printing of MR coils by printing channels into SLA resin (which may be multiple materials). These channels are then filled / coated / plated with one or more materials to obtain an electronic circuit suitable for probe and / or generate and / or passively homogenize B0 of the electromagnetic field. The channels are designed / filled to inherently accommodate all the electronic components required for the electronic circuit (resistors, capacitors, inductors) and to fit snugly to the patient's specific anatomical tissue. This makes it possible to tune / match / decouple / detune the electronic circuit without the need to manually solder discrete electronic components to the 3D printed electronic circuit. A novel multi-material filling technique for the channels is applied to maximize the efficiency of the electronic circuit.

[0011] The present invention can be further summarized in the following statement.

[0012] 1. An MRI or NMR measurement configuration comprising one or more 3D printed hollow elements adapted to the shape of an object to be measured, wherein in one or more of the 3D printed elements, the wall of the element is made of a UV-curable electrically nonconductive material that forms one or more channels, and in at least one of the elements having the wall, the channel is composed of at least two material plugs of at least two different immiscible materials selected from the group consisting of dielectric materials, electrically conductive materials, and materials having high electrical resistance.

[0013] 2. The material plug has the configuration described in Statement 1, which forms an electrical circuit or some part thereof.

[0014] 3. The elements form a loop, as described in statement 1 or 2.

[0015] 4. The configuration according to statement 1 or 2, wherein the channel comprises an immiscible material plug of a dielectric material, a conductive material, and a material having high electrical resistance.

[0016] 5. The configuration according to any one of Statements 1 to 4, wherein the channel comprises a conductive material and further comprises a dielectric material or a material having a high electrical resistance.

[0017] 6. The configuration according to any one of Statements 1 to 5, wherein in all of the one or more 3D printing elements, the wall of the element is made of a UV curable material forming one or more channels.

[0018] 7. The configuration according to any one of Statements 1 to 6, wherein the wall of the element made of a UV curable material forms a single channel.

[0019] 8. The configuration according to any one of Statements 1 to 7, which is adapted to anatomical tissues of the body or body parts of an animal or human subject.

[0020] 9. The configuration according to any one of Statements 1 to 8, wherein one or more of the electric circuits are connected to one or more electronic circuit boards, thereby enabling the control of the alignment, synchronization, detuning, and decoupling of the individual elements.

[0021] 10. The configuration according to any one of Statements 1 to 9, wherein the 3D printing element is manufactured by VAT polymerization or direct material melting printing.

[0022] 11. The configuration according to any one of Statements 1 to 10, wherein the 3D printing element is flexible.

[0023] 12. The configuration according to any one of Statements 1 to 11, further comprising an additional channel having a material for controlling the temperature of the element.

[0024] 13. Use of the configuration according to any one of Statements 1 to 12 in one or more roles selected from transmission of RF signals, reception of RF signals, or homogenization of magnetic fields.

[0025] 14. A method of fabricating the configuration according to any one of Statements 1 to 12, comprising: a) preparing geometric data of the object to be measured; b) defining an outer shape of a configuration of loops or elements conforming to the shape of the object by electromagnetic simulation and / or design calculation and / or generative modeling resulting in a CAD design of the configuration; c) calculating a component and sequence delivery of a dielectric material, a conductive material, or a material having a high electrical resistance for realizing the electronic circuit or some of its parts; d) 3D printing the configuration of the element or loop according to the calculations in steps b) and c), wherein the walls of the element or the loop form one or more channels and are made of a UV curable electrically non - conductive material; e) filling at least one channel in at least one of the loops or elements prepared in d) with at least two material plugs of at least two different immiscible materials selected from the group consisting of a dielectric material, an electrically conductive material, and a material having a high electrical resistance according to the component and sequence delivery calculated in step c); The method comprising the above steps.

[0026] 15. The method according to Statement 14, wherein the element is printed as a loop.

[0027] 16. The method according to Statement 15, wherein filling the channel or a designated part of the channel with an inductive component is performed by filling the designated part of the channel with a conductive material, or by electroplating either the inner wall or the outer wall of the designated part of the coil configuration with a conductive layer.

[0028] 17. The method according to statement 15 or 16, wherein the capacitive component of the equivalent RLC circuit is manufactured by manipulating the length, shape, and sequence of material plugs inside the section of the channel designated for the capacitive component.

[0029] 18. The method according to statement 14 or 16, wherein the inductive component of the equivalent RLC circuit is manufactured by manipulating the length, shape, and sequence of material plugs inside the section of the channel designated for the inductive component.

[0030] 19. The method according to statement 15 or 16, wherein the resistance of the equivalent RLC circuit is obtained by manipulating the length, shape, and sequence of material plugs inside the section of the channel designated for the resistive component.

[0031] 20. The method according to any one of statements 15 to 19, wherein the capacitive component is alternately filled by filling the channels with a conductive fluid and a highly dielectric fluid, and further connections are made to connect the loop or the elements such that the channels of different elements or loops form multiple capacitors in parallel rather than in the initial series configuration.

[0032] 21. The method according to any one of statements 15 to 20, further comprising the step of designing the electronic circuit that satisfies the performance requirements based on experimental requirements using electromagnetic simulation software.

[0033] 22. The method according to any one of statements 15 to 21, wherein multiple loops or elements are connected and multiple channels are filled with a single sequence of material plugs.

[0034] 23. An MRI or NMR measurement configuration comprising one or more 3D printed loops adapted to the shape of an object to be measured, wherein the one or more 3D printed loops include channels comprising immiscible material plugs of at least two materials selected from the group consisting of dielectric materials, electrically conductive materials, and materials having high electrical resistance, and these material plugs form an electrical circuit or a portion thereof.

[0035] 24. The configuration according to Statement 23, wherein the channel comprises an immiscible material plug containing a dielectric material, a conductive material, and a material having high electrical resistance.

[0036] 25. The configuration described in Statement 23 or 24, which is adapted to the anatomical tissue of the body or body part of an animal or human subject, such as the head, torso, or knee.

[0037] 26. The configuration according to any one of statements 23 to 25, wherein one or more of the electrical circuits are connected to one or more electronic circuit boards, thereby enabling the control of matching, tuning, detuning, and decoupling of the individual loops.

[0038] 27. The 3D printed loop is manufactured by VAT polymerization or direct material melt printing, as described in any one of statements 23-27.

[0039] In this specification, any additive manufacturing method can be used. Examples include VAT polymerization (stereolithography, digital photoprocessing, continuous digital photoprocessing, direct material melting (melt deposition modeling, Arburg plastic freeforming), sheet lamination (laminate manufacturing), direct energy deposition (laser engineering net shaping, electron beam additive manufacturing), binder jetting, material jetting / ink jetting (multi-jet modeling / poly-jetting nanoparticle jetting drop-on-demand), and powder bed fusion bonding (multi-jet fusion, selective laser sintering, selective laser melting, electron beam melting).

[0040] 28. The 3D printed loop is made of a non-conductive polymer, as described in any one of statements 23 to 27.

[0041] 29. The dielectric material has a dielectric constant of at least 3, as described in any one of statements 23 to 28.

[0042] 30. The conductive material has a temperature of 10°C at 20°C. 2 A configuration described in any one of statements 23 to 29, having conductivity greater than S / m.

[0043] 31. The material having high resistance has a resistivity greater than 10 Ohm / m, and is configured as described in any one of statements 23 to 30.

[0044] 32. The immiscible material plug has a viscosity of at least 0.1 mPa*s, and is configured as described in any one of statements 23 to 31.

[0045] 33. The 3D printing loop is flexible, as described in any one of statements 23 to 32.

[0046] 34. The configuration according to any one of statements 23 to 33, further comprising an additional channel having a material for controlling the temperature of the loop.

[0047] 35. Use of the configuration described in any one of statements 23-34 in one or more roles selected from transmitting RF signals, receiving RF signals, or equalizing magnetic fields.

[0048] 36. A method for producing the configuration described in any one of statements 23 to 34, a) Prepare geometric data of the object to be measured, b) Defining the external shape of the loop configuration that conforms to the shape of the object by electromagnetic simulation and / or design calculation and / or generation modeling that results in a CAD design of the loop configuration, c) Calculating the quantities and sequence delivery of dielectric materials, conductive materials, or materials with high electrical resistance that make up the electronic circuit or some parts thereof. This results in a digital plug flow sequence. d) 3D printing the loop configuration according to the calculations in steps b) and c), e) Filling the internal channel of the loop with the dielectric material, the conductive material, and the material having high resistance according to the calculation in step system c), Methods that include...

[0049] 37. The method according to Statement 36, wherein filling the internal channel of the inductive component is done by filling the designated portion of the loop with a conductive material, or by electroplating either the internal or external wall of the designated portion of the coil configuration with a conductive layer.

[0050] 38. The method according to statement 36 or 37, wherein the capacitive component of the equivalent RLC circuit is manufactured by manipulating the length, shape, and sequence of material plugs inside the section of the channel designated for the capacitive component.

[0051] 39. The method according to statement 36, wherein the resistance of the equivalent RLC circuit is obtained by manipulating the length, shape, and sequence of material plugs inside the section of the channel designated for the resistive component.

[0052] 40. The method according to any one of statements 36 to 39, further comprising the steps of connecting an MCX connector to each individual loop in the designated section of the CAD design, and fixing the MCX connector with a durable resin to enable the connection to the required circuit board.

[0053] 41. The method according to any one of Statement 36, wherein the capacitive component is alternately filled by filling the channels with a conductive fluid and a highly dielectric fluid, and further secondary channels connect these channels such that these channels form multiple capacitors in parallel rather than in the initial series configuration.

[0054] The filling of this capacitor configuration is carried out in the following two stages. Stage 1: Filling a plug sequence within a single channel. Precise positioning is possible by (i) digital plug generation, (ii) known quantities of both the channel and the injected plug, and (iii) increased air pressure (blocked off using custom printing on the flexible material) and prevention of injection into side channels due to pressure through angles or from a conductive liquid reservoir. Stage 2: Removal of side channel blockage and injection via vacuum method. At this time, the capacitors are connected in parallel, increasing their capacitance.

[0055] 42. The method according to any one of statements 36 to 41, further comprising the step of designing the electronic circuit that satisfies the performance requirements based on experimental requirements using electromagnetic simulation software.

[0056] 43. The method according to statement 36, wherein the filling is performed by an automated flow control valve control system.

[0057] 44. The method according to any one of statements 36-44, wherein multiple loops are connected and the multiple loops are filled in a single sequence of material plugs. As an alternative to filling each individual loop of the phased array individually, all loops are temporarily connected head-to-tail using connectors to allow filling in a single operation.

[0058] 45. The method according to any one of statements 36 to 44, wherein, prior to step e), some portion of the internal channel wall of the loop is covered with a layer that alters its physiological and chemical properties. This layer may exhibit any of omniphobic, hydrophobic, or oleophobic properties, acting as a slip layer for the material plug.

[0059] 46. ​​The method according to any one of statements 36 to 45, wherein, prior to step e), some portion of the channel of the loop is treated to change the surface roughness of the channel wall. [Brief explanation of the drawing]

[0060] [Figure 1]This is an overview of the proposed workflow: (1) Input data, such as the anatomical tissue of the subject whose coil shape must be matched, and the coil function (RF receiver, RF transmitter, active shim, etc.) are acquired. (2) An electronic circuit scheme is generated using magnetic field electronic circuit simulation software. (3a) This electronic circuit is converted into a CAD design consisting of a complex channel network using generative modeling techniques. (3b) This CAD design, along with the required electronic components and their respective properties (resistance, capacitance, inductance), is used as input to generate a digital multi-material plug flow sequence (proprietary software). (4) The CAD design is printed using a stereolithography-based 3D printing method. (5) The 3DP electronic circuit is filled with the multi-material plug flow sequence, resulting in a ready-to-use coil. [Figure 2] This is a schematic diagram illustrating how plug flow is generated in an Elveflow setup. Flow controllers and valves are simultaneously controlled to adjust the volume and sequence of liquid plugs specified for each specific component of the channel circuit. Flow sensors can be added to ensure / calibrate the liquid-liquid plug flow system. [Figure 3] This is a diagram showing a reference capacitor element. [Figure 4] This diagram shows a triple-channel capacitor. [Figure 5] This diagram shows a two-stage filled channel capacitor. [Figure 6] This figure shows a two-stage filling method for parallel channel capacitors: In the first stage of the two-stage filling method for parallel channel capacitors, the primary channel is filled using a sequential liquid-liquid-liquid plug flow controlled by an Erbe flow setup. In the second stage (after the primary channel is filled), the secondary channel is filled using a vacuum filling method. In this way, the individual capacitors are arranged in parallel, and the maximum volumetric capacitance is greatly increased. [Figure 7] (Left) This is a schematic diagram showing how this circuit is translated into a CAD design consisting of a complex network of primary and secondary channels (Stage 0). In the first stage of the two-stage filling method for parallel channel capacitors, the primary channel is filled using a sequential liquid-liquid-liquid plug flow controlled by an Erbe flow setup. In the second stage (after the primary channel is filled), the secondary channel is filled using a vacuum filling method. In this way, the individual capacitors are arranged in parallel, and the maximum volumetric capacitance is greatly increased. (Right) This is a diagram showing the electronic circuit of an RF coil with the same adjustment circuit. [Figure 8] This diagram shows that additional channels can be used for temperature control in addition to the MR channel: (A) The channel can be conformally wrapped around the MR coil channel or conformally fitted to the analyte. (B) The temperature control channel can be placed inside (enclosed) the MR coil channel. (C) The MR coil channel can be placed inside (enclosed) the temperature control channel. [Figure 9] This diagram shows the filling support section: The filling support section connects to all individual inlet / outlet ports (black arrows) of the complex coil array. This method connects all individual channels to the main (single) channel of the filling support section. [Modes for carrying out the invention]

[0061] The present invention relates to the manufacture of electronic circuits suitable for use in NMR / MRI / MRS and other MR-related applications requiring cost-effective and time-efficient complex electronic circuit geometry. More specifically, the present invention provides the production of subject-specific (and / or general) RF and / or active shim coil and / or passive shim configurations. The present invention can also be used in other applications requiring electronic circuits such as gradient magnetic field coils and impedance sensing.

[0062] A first aspect of the present invention relates to an MRI or NMR measurement configuration comprising one or more 3D printed hollow elements adapted to the shape of an object to be measured, wherein in one or more of the 3D printed elements, the wall of the element is made of a UV-curable electrically nonconductive material that forms one or more channels, and in at least one of the elements having the wall, the channel is composed of at least two material plugs of at least two different immiscible materials selected from the group consisting of dielectric materials, electrically conductive materials, and materials having high electrical resistance.

[0063] Typically, these material plugs form an electrical circuit or some part of it.

[0064] Typically, the above elements form a loop. In some applications, such as passive shimming, the elements can have other shapes.

[0065] In the embodiment of the above configuration, the channel comprises an immiscible material plug made of a dielectric material, a conductive material, and a material having high electrical resistance.

[0066] In the embodiment of the above configuration, the channel comprises a conductive material and further comprises a dielectric material or a material having high electrical resistance.

[0067] In the embodiment of the above configuration, in all of the one or more 3D printed elements, the element walls are made from a UV-curable material that forms one or more channels.

[0068] In a particular embodiment of the above configuration, the wall of the element, fabricated from a UV-curable material, forms a single channel.

[0069] Typically, the above configuration is adapted to the anatomical tissue of the body or body part of an animal or human subject, such as the head or torso. While the above configuration is usually applied externally to animals or humans, applications where the configuration is used internally are also envisioned. Similarly, applications where the above configuration is used in plants and other living organisms, as well as inanimate objects, are anticipated.

[0070] In the embodiment of the above configuration, one or more of the electrical circuits are connected to one or more electronic circuit boards, thereby enabling control of matching, tuning, detuning, and decoupling of individual elements.

[0071] In the embodiment of the above configuration, the 3D printed element is manufactured by VAT polymerization (stereolithography, digital photoprocessing, continuous digital photoprocessing, direct material melting (melt deposition modeling, Arburg plastic freeforming), sheet lamination (laminate manufacturing), direct energy deposition (laser engineering net shaping, electron beam additive manufacturing), binder jetting, material jetting / ink jetting (multi-jet modeling / poly-jetting nanoparticle jetting drop on demand), and powder bed fusion bonding (multi-jet fusion, selective laser sintering, selective laser melting, electron beam melting).

[0072] In the embodiment of the above configuration, the 3D printed element is flexible.

[0073] In the embodiment of the above configuration, the configuration further comprises an additional channel having a material for controlling the temperature of the element. This temperature control channel can be applied to the outside of the element. In a particular embodiment in which the element has two or more channels, one of the channels located inside the element can be used for temperature control.

[0074] In this specification, a dielectric material has, for example, a dielectric constant of at least 3.

[0075] In this specification, conductive materials are defined as, for example, 10°C at 20°C. 2 It has a conductivity greater than S / m.

[0076] In this specification, a material having high resistance is defined as having a resistivity greater than, for example, 10 Ohm / m.

[0077] In this specification, the immiscible material plug has, for example, a viscosity of at least 0.1 mPa*s.

[0078] The above configuration of the present invention differs from Non-Patent Document 2 cited above, in that, for example, the element or loop is entirely fabricated from a non-electrically conductive UV-curable material. The UV-curable material of the element or loop forms the wall of the internal channel. Different material plugs are located within this channel along the longitudinal axis of the channel.

[0079] The above configuration of the present invention differs from Non-Patent Document 3 cited above, for example, in that the UV-curable material is non-electrically conductive.

[0080] Another aspect of the present invention relates to the use of the above configuration in one or more roles selected from transmitting RF signals, receiving RF signals, or homogenizing magnetic fields.

[0081] Another aspect of the present invention is a method for manufacturing the configuration described in the first aspect, a) A step of preparing geometric data of the object to be measured, b) A step of defining the external shape of the loop or element configuration that conforms to the shape of the object by electromagnetic simulation and / or design calculation and / or generation modeling that results in a CAD design of the above configuration, c) A step of calculating the quantity and sequence delivery of dielectric material, conductive material, or material having high electrical resistance that will make up an electronic circuit or some part thereof, d) A step of 3D printing the configuration of an element or loop according to the calculations in steps b) and c), wherein the walls of the element or loop are made of a UV-curable, electrically non-conductive material that forms one or more channels, The steps include filling at least one channel in at least one of the loops or elements prepared in e)d) with at least two material plugs of at least two different immiscible materials selected from the group consisting of dielectric materials, electrically conductive materials, and materials having high electrical resistance, in accordance with the quantities and sequence delivery calculated in step system c), This includes methods.

[0082] Typically, elements are printed as loops. Other shapes or configurations can be used for applications such as active shimming.

[0083] Typically, filling a channel or a specified portion of a channel with an inductive component is done by filling the specified portion of the channel with a conductive material, or by electroplating either the inner or outer wall of a specified portion of the coil configuration with a conductive layer.

[0084] In embodiments of these methods, the capacitive component of the equivalent RLC circuit is manufactured by manipulating the length, shape, and sequence of material plugs inside the channel sections designated for the capacitive component.

[0085] In embodiments of these methods, the inductive component of the equivalent RLC circuit is manufactured by manipulating the length, shape, and sequence of material plugs inside the channel sections designated for the inductive component.

[0086] In embodiments of these methods, the resistance of the equivalent RLC circuit is obtained by manipulating the length, shape, and sequence of material plugs inside the channel section designated for the resistive component.

[0087] In embodiments of these methods, the capacitive components are alternately filled by filling the channels with a conductive fluid and a highly dielectric fluid, and further connections are made to connect the loops or elements such that the channels of different elements or loops form multiple capacitors in parallel rather than in the initial series configuration.

[0088] Embodiments of these methods include a further step of designing an electronic circuit that meets performance requirements based on experimental requirements using electromagnetic simulation software.

[0089] In embodiments of these methods, multiple loops or elements are connected, and multiple channels are filled with a single sequence of material plugs.

[0090] Embodiments of these methods further include the steps of connecting MCX connectors to each individual loop within a designated section of a CAD design and fixing the MCX connectors using durable resin to enable the required circuit board connections.

[0091] In embodiments of these methods, the capacitive components are alternately filled by filling the channels with a conductive fluid and a highly dielectric fluid, and further secondary channels connect these channels so that they form multiple capacitors in parallel rather than in the initial series configuration.

[0092] The filling of such a capacitor configuration is carried out in the following two stages. Stage 1: Filling the plug sequence in a single channel. Precise positioning is possible by (i) digital plug generation, (ii) known quantities of both the channel and the injected plug, and (iii) increased air pressure (blocked off using custom printing on the flexible material) and prevention of injection into the side channel due to pressure through the angle or from a conductive liquid reservoir. Stage 2: Removal of side channel blockage and injection via vacuum method. At this time, the capacitors are connected in parallel, increasing their capacitance.

[0093] Embodiments of these methods further include the step of designing an electronic circuit that satisfies performance requirements based on experimental requirements using electromagnetic simulation software.

[0094] In embodiments of these methods, filling is performed by an automated flow control valve control system.

[0095] In embodiments of these methods, multiple loops are connected, and these multiple loops are filled with a single sequence of material plugs. As an alternative to filling each individual loop of the phased array individually, all loops are temporarily connected head-to-tail using connectors to enable filling in a single operation.

[0096] In embodiments of these methods, prior to step e), some portion of the inner channel wall of the loop is coated with a layer that alters its physiological and chemical properties. Such a layer may exhibit omniphobic, hydrophobic, or oleophobic properties, acting as a slip layer for the material plug.

[0097] In embodiments of these methods, prior to step e), some portion of the loop channel is treated to change the surface roughness of the channel wall.

[0098] The following is a detailed, but non-limiting, list of various coil configurations to which the present invention can be immediately applied.

[0099] RF coil - Receive mode only, transmit mode only, transceiver RF coil - Volume coils (e.g., circularly polarized coils, orthogonal coils, birdcage coils, crossed coils, Helmholtz pair coils, paired saddle coils, single-turn solenoids, etc.) - Surface coils (e.g., array coils, body wrap-around coils, linear polarization coils, saddle coils, etc.) - Transmission line resonators and / or resonant circuit coils - NMR probes (transmit and receive modes) - RF coil with conformal heating / cooling

[0100] Active shim coil - Self-cooling, conformal cooling - Spherical harmonic coils (Maxwell coils, Helmholtz coils, etc.) - Multi-coil array

[0101] Other specific uses: - 3D printed phantom with / without embedded coils - 3D printed personal immobilization device for MRI-guided radiotherapy, housing an RF coil embedded in the immobilization device. - Passive shim configuration

[0102] Starting with patient-specific input data (e.g., anatomical tissue data to determine coil conformal fit, coil type, etc.), an electronic circuit that meets the requirements of the coil to be manufactured is simulated. This electronic circuit is then converted into a CAD design consisting of a complex channel network. The software required for this step uses generative modeling techniques.

[0103] Electronic circuit components are considered in the CAD design. The CAD design for each unit coil (array coils consist of multiple unit coils) consists of a single uninterrupted channel. This single uninterrupted channel branches to form a complex network of primary and secondary channels. The single channel is filled to maximize the performance of each electronic component (resistors, inductors, capacitors). Resistor components are filled with high-resistance material, inductors with high-conductivity material, and capacitors with alternating high-dielectric and conductive materials. As a result, the primary channel is filled with a sequence of material plugs. The filling of the primary channel is pre-calculated and automated by using the Erbeflow multi-material injection method. The software calculates the pressure and valve timing required to create material plugs of the correct length to properly fill the primary channel. The length of each plug is calculated from the pre-generated CAD design. A schematic overview of the proposed working method is shown in Figure 1.

[0104] 3D printed channels may or may not be pre-treated to make their internal walls functional (e.g., altering surface tension behavior, surface roughness, etc.) to aid in the filling / plating of the channel itself. This pre-treatment may have the following chemical properties, for example: For example, by applying an omniphobic coating, the contact angle of the resin, and consequently its wetting properties, can be chemically manipulated. -For example, the electrical properties of a resin can be manipulated by coating it with a conductive seed layer.

[0105] The above pretreatment can also be mechanical; for example, a halftoning process can be applied during the curing of each individual layer to induce surface roughness on the internal channel walls of an SLA print. Increasing the surface roughness of the internal channel walls can be used to increase the contact angle of the liquid inside the channel (Cassie's Law). An increased contact angle is desirable when filling the channel with multiple liquids. This is because, by reducing the wettability of each liquid, each individual "liquid plug" maintains its shape as it is extruded through the channel and does not leave a liquid "tail" behind.

[0106] The composition of the resin(s) can be modified to achieve a specific function of the final resin component. - The resin(s) can be modified to include particles that add desired functionality to the final 3D printed part (e.g., high dielectric particles that enhance the dielectric properties of the resin). - The resin(s) can be made biocompatible. - The resin(s) can be made flexible.

[0107] The required electronic circuitry is converted into a CAD design consisting of a channel network. The channel network consists of a single primary channel, the "primary channel," which is connected to secondary channels at specific points. The purpose of the secondary channels is to ensure that capacitors are arranged in parallel rather than in series in the final CAD design, thus ensuring high capacitance (see Capacitor Design).

[0108] The primary channel is designed to mimic an electronic circuit. Specifically, some sections of the primary channel are designed to feature resistive structures, others to feature inductors, and still others to feature capacitors. Different electronic CAD components require filling with different materials to maximize the efficiency of energy transfer in the resonant coil. The primary channel is continuously filled with plugs of different materials of certain lengths corresponding to the required length in a specified 3D printed channel of that particular electronic component. The calculation of plug length / quantity is based on the channel geometry (CAD design). This information is translated by software that simultaneously controls the flow controller and valves of the Elbe flow system to adjust the liquid-liquid plugs. In one embodiment of the present invention, three liquid materials are used to form (1) conductive plugs, (2) high dielectric plugs, and (3) high resistive plugs. However, the method of the present invention can be estimated to fill a complex 3D printed channel network with any amount of liquid having a specific function. Figure 7 shows a schematic overview of how the plug flow sequence required to fill the 3D printing channels is generated.

[0109] CAD design can take into account not only the inductor loop but also (all) other components of the electronic circuit. As a result, coils that can be tuned / matched / detuned / decoupled with other coil circuits are obtained as is. Soldering electronic components to the coil after fabrication is not necessarily required.

[0110] The resistance of an electronic circuit can be manipulated by manipulating the internal length, shape, curvature, and material plug of the channel section specified for a resistive component.

[0111] The inductance of an electronic circuit can be manipulated by manipulating the length / shape / number, size, and configuration / material of the plug inside the channel section designated for the inductive component.

[0112] The capacitance of an electronic circuit can be manipulated by manipulating the internal length, shape, and material plug of the channel section specified for a capacitive component (important for tuning / matching RF coils).

[0113] In CAD design, the following various capacitor configurations can be used. 1. Reference Capacitor: The channel is filled with conductive material, and each electrode is formed. The SLA resin between the channels acts as a dielectric material. Maximum achievable capacitance / mm 3 Complex shapes can be designed to increase the capacitance (e.g., spiral capacitors, parallel plate capacitors, etc.). See Figure 3. 2. Triple-channel capacitor: Two channels are filled with conductive material to form the electrodes of the capacitor, and a third channel filled with a highly dielectric material is placed between these electrode channels to increase the capacitance. See Figure 4. 3.2-Stage Capacitor: A single continuous channel (primary channel) is alternately filled with conductive fluid and highly dielectric fluid (see plug flow filling). The secondary channel connects the primary channel so that the primary channel forms multiple capacitors in parallel rather than in the initial series configuration. See Figure 5. Filling of this capacitor configuration is carried out in two stages (Figure 6). Stage 1: Filling the plug sequence in the primary channel. Precise positioning is possible by (i) digital plug generation, (ii) known quantities of both the channel and the injection, and (iii) prevention of injection into the side channel due to air pressure (blocked off using custom printing in the flexible material) and pressure through the angle or from the conductive liquid reservoir. Stage 2: Removal of side channel blockage and injection via vacuum method. Since the side channel is short, there is no problem with the plug moving (vacuum is reached rapidly). The capacitor is then connected in parallel, increasing the capacitance.

[0114] A capacitor can be made into a variable capacitor (allowing for adjustment of capacitance) or a non-variable capacitor by manipulating the amount of dielectric material / size of the conductive plug using pressure changes after the coil has been filled and assembled.

[0115] An example of how electronic circuits (RF coils and their integrated adjustment circuits) can be converted to CAD design and digital plug flow sequencing is briefly described below. -Filling method: Two different filling methods are used as embodiments of the manufacturing method of the present invention. Filling method 1: Direct injection. By applying pressure to the liquid plug, the plug fills the channel. Filling Method 2: Vacuum Filling. The inlet is covered with liquid metal. The 3D printed channel is placed inside a vacuum chamber to remove air. By releasing the vacuum, the surroundings return to atmospheric pressure, and the metal is pushed into the channel. -material Any combination or derivative of the following materials can be used for multi-material plug flow: -Conductive materials: Conductive plug materials used to fill channel components requiring high conductivity (e.g., inductor components, capacitor electrode components) can be filled with eutectic metal. This eutectic metal may or may not be mixed with conductive nanoparticles (e.g., silver, gold). Alternatively, the inner or outer walls of the channel can be selectively plated with a conductive material such as copper. Hot injection of conductive metal (e.g., Ag) can also be used.

[0116] The disclosed 3D printing method utilizes a conductive material with a higher resistivity than copper, which lowers the signal-to-noise ratio (SNR) of the coil. However, the greater skin thickness of the eutectic metal partially compensates for this adverse effect. Furthermore, the disclosed manufacturing method allows the coil design to conform to the patient's anatomical tissue, which works to the advantage of the SNR, as the SNR is inversely proportional to the square of the distance from the center of the coil.

[0117] Functional liquids / gels / pastes / slurries containing high-dielectric (high-k) particles are used as high-dielectric materials in plug flow. Some particles, such as oxides (e.g., Br / Sr titanates), exhibit very high dielectric constants and can be easily dispersed in aqueous or non-aqueous solvents with the help of dispersants. This makes these particles particularly useful in forming high-k slurries. The effective dielectric constant of the final slurry is determined by the Maxwell-Garnett model.

number

[0118] Some parts of a CAD circuit include redundant sections that do not function after the two-stage filling method is complete. Since these redundant sections can potentially add undesirable noise to the electronic circuit, they can be "blocked" by filling them with "decoupling plugs." This decoupling material has material properties similar to those of SLA resin.

[0119] When a high current is passed through a conductive channel, undesirable heating can occur. This heating can result from (a) vibration (friction) of the conductive channel—from the Lorentz force generated by immersing the current through the copper wire in a magnetic field—and / or (b) through a direct (resistive) electrical mechanism. The release of thermal energy can lead to thermally induced frequency shifts and shim field changes. Therefore, heat must be removed from the 3D printed conductive channel. Alternatively, it may be desirable to cryo-cool the coil to increase the SNR. This can be done in embodiments of the present invention by designing a cooling channel around the probe, or by adding a cooling channel inside / outside the main conductive channel of the main inductor of the RLC circuit. A cooling liquid / gas (e.g., water, nitrogen) is circulated through the cooling channel to remove the undesirable heat generated by the probe. The cooling channel can be conformally designed around the conductive channel to closely follow the shape or profile of the conductive channel, enabling fast and efficient heat removal. Similarly, heating fluid can be circulated through the channel to enable precise temperature control of the object being scanned (for example, when it is necessary to keep an anesthetized subject warm). A schematic diagram of an MR RF probe having (i) a conformal temperature control channel, (ii) an internal temperature control channel, and (iii) an external temperature control channel is shown in Figure 8. Any combination of these temperature control channels can be used (for example, a combination of an internal cryo-cooling channel and an external heating channel that does not harm the subject).

[0120] Generative modeling is used to simplify the construction of complex 3D channel networks required for CAD design. In generative modeling, 3D objects are replaced by object generation operations. Generative modeling gains efficiency by creating high-level shape operators from low-level shape operators. Any sequence of processing steps can be grouped to create a new join operator. This new join operator can use not only basic operators but also other join operators. Specific values ​​can be easily replaced with parameters, thereby separating data from operations. The same processing sequence can be applied to different input datasets. For example, different shapes can be generated using the same data by applying different join operators from a library of domain-dependent modeling operators. This technique makes it possible to create very complex objects from only a few high-level input parameters, such as a style library [https: / / en.wikipedia.org / wiki / Generative_Modelling_Language].

[0121] When multiple loops are required in a coil design (e.g., an RF receiver surface array coil), each loop must be filled individually. To improve the time efficiency of filling these complex coil designs, a filling aid is used. See Figure 9. The filling aid fits into all individual inlet / outlet ports (black arrows) of the complex coil array. It interconnects all individual channels into the main (single) channel of the filling aid. This reduces the number of inlet / outlet ports to just one (main inlet / outlet). The filling aid is removed after the complex coil array has been filled.

[0122] Drawing translation Figure 1 Input Data Simulated Electronic Circuit CAD design CAD design 3DP coil 3DP coil Plug flowsequence Filled coil Electromagnetic field simulations Electronic circuit simulations Generative modeling Material Specifications Channel dimensions Elveflow multi-material injection flow method Figure 2 pressure controller Valvecontroller MUX WIRE (Multiple Wire) Reservoir Conductivemetal Decoupling liquid Valve High dielectric slurry Conductive alloy reservoirs Conductive alloy filled channel High dielectric filled channel Decoupling liquid filled channel Figure 3 Repeating unit Figure 4 Filling inlet Filling inlet Capacitor plate Repeating unit Dielectricum (dielectric) Figure 5 Filling inlet Filling inlet Plugflow Flagflow Repeating unit Figure 6 Stage Figure 7 Conductive alloy reservoirs Conductive alloy filled channel High dielectric filled channel Decoupling liquid filled channel Unfilled channel Stage Plug flowcontroller Flag flow controller Equivalent RF coil circuit Coil Tune and match Figure 8 3DP MR cartridge 3DP MR coil Conformal temperature control channel Temperature control channel Figure 9 Maininlet / outlet Filling aid Coil array コイルアレイ

Claims

1. An MRI or NMR measurement configuration comprising one or more 3D printed hollow elements adapted to the shape of the object to be measured, wherein in one or more of the 3D printed hollow elements, the walls of the 3D printed hollow elements are made from a UV-curable, electrically non-conductive material that forms one or more channels. A configuration characterized in that at least one of the 3D printed hollow elements having the wall, the channel comprises at least two material plugs of at least two different immiscible materials selected from the group consisting of capacitors alternately filled with dielectric and electrically conductive materials, inductors of electrically conductive materials, and resistors of materials having high electrical resistance.

2. The configuration according to claim 1, wherein these material plugs form an electrical circuit or some part thereof.

3. The configuration according to claim 1 or 2, wherein the 3D printed hollow element forms a loop.

4. The configuration according to claim 1 or 2, wherein the channel includes immiscible material plugs of at least two different immiscible materials selected from the group consisting of capacitors alternately filled with dielectric and electrically conductive materials, inductors of electrically conductive materials, and resistors of materials having high electrical resistance.

5. The configuration according to any one of claims 1 to 4, wherein the channel includes an inductor made of an electrically conductive material plug, and further includes a capacitor or a resistor made of a material having high electrical resistance, which is alternately filled with a dielectric material and an electrically conductive material.

6. The configuration according to any one of claims 1 to 5, wherein in all of the one or more 3D printed hollow elements, the walls of the 3D printed hollow elements are made from a UV-curable material that forms one or more channels.

7. The configuration according to any one of claims 1 to 6, wherein the wall of the 3D printed hollow element made from a UV-curable material forms a single channel.

8. The configuration according to any one of claims 1 to 7, which is adapted to the anatomical tissue of the body or body part of an animal or human subject.

9. These material plugs form an electrical circuit or some part thereof. The configuration according to any one of claims 1 to 8, wherein one or more of the electrical circuits are connected to one or more electronic circuit boards, thereby enabling control of matching, tuning, detuning, and decoupling of the 3D printed hollow elements.

10. The 3D printed hollow element is manufactured by VAT polymerization or direct material melt printing, the configuration according to any one of claims 1 to 9.

11. The configuration according to any one of claims 1 to 10, wherein the 3D printed hollow element is flexible.

12. The configuration according to any one of claims 1 to 11, further comprising an additional channel having a material for controlling the temperature of the 3D printed hollow element.

13. Use of the configuration according to any one of claims 1 to 12 in one or more roles selected from transmitting an RF signal, receiving an RF signal, or equalizing a magnetic field.

14. A method for manufacturing the configuration described in any one of claims 1 to 12, a) Prepare the geometric data of the object to be measured, b) Defining the external shape of the loop or 3D printed hollow element configuration that conforms to the shape of the object by electromagnetic simulation and / or design calculation and / or generation modeling that results in a CAD design of the above configuration, c) Calculating the quantities and sequence delivery of dielectric materials, conductive materials, or materials with high electrical resistance that make up an electronic circuit or some part thereof, d) 3D printing the 3D printed hollow element or loop configuration according to the calculations in steps b) and c), wherein the walls of the 3D printed hollow element or loop are formed of one or more channels and are made from a UV-curable, electrically non-conductive material. e) Fill the loop prepared in d) with at least one channel in at least one of the 3D printed hollow elements or the loop of the 3D printed hollow element with at least two material plugs of at least two different immiscible materials selected from the group consisting of capacitors alternately filled with dielectric and electrically conductive materials, inductors of electrically conductive materials, and resistors of materials having high electrical resistance, according to the quantities and sequence delivery calculated in step system c), Methods that include...

15. The method according to claim 14, wherein the 3D printed hollow element is printed as a loop.

16. The method according to claim 15, wherein filling a channel or a designated portion of a channel with an inductive component is performed by filling the designated portion of the channel with a conductive material, or by electroplating either the inner wall or the outer wall of the designated portion of the coil configuration with a conductive layer.

17. The method according to claim 15 or 16, wherein the capacitive component of the equivalent RLC circuit is manufactured by manipulating the length, shape, and sequence of material plugs inside the channel section designated for the capacitive component.

18. The method according to claim 14 or 16, wherein the inductive component of the equivalent RLC circuit is manufactured by manipulating the length, shape, and sequence of material plugs inside the section of the channel designated for the inductive component.

19. The method according to claim 15 or 16, wherein the resistance of the equivalent RLC circuit is obtained by manipulating the length, shape, and sequence of material plugs inside the channel section designated for the resistive component.

20. The method according to claim 17, wherein the capacitive components are alternately filled by filling the channels with a conductive fluid and a highly dielectric fluid, and further connections are made to connect the loop or the 3D printed hollow elements such that the channels of different 3D printed hollow elements or loops form multiple capacitors in parallel rather than in an initial series configuration.

21. The method according to any one of claims 15 to 20, further comprising the step of designing the electronic circuit that satisfies performance requirements based on experimental requirements using electromagnetic simulation software.

22. The method according to any one of claims 15 to 21, wherein multiple loops or 3D printed hollow elements are connected and multiple channels are filled with a single sequence of material plugs.

Images