A wearable thin-film magnetic resonance imaging (MRI) receive coil integrated with a magnetic resonance imaging (MRI)-guided transcranial focused ultrasound (tFUS) treatment system

Abstract

A magnetic resonance imaging (MRI) receiving coil device and a method of manufacturing the same are provided. The MRI receiving coil device includes a thin film substrate layer configured in a dome shape and a coil array disposed around the outer surface of the thin film substrate layer. A thin film cover layer is disposed on the outer surface of the thin film substrate layer such that the coil array is disposed between the thin film cover layer and the thin film substrate layer. The MRI receiving coil device further includes an end ring that engages the thin film substrate layer and the thin film cover layer such that a watertight seal is formed around the coil array between the thin film substrate layer, the thin film cover layer, and the end ring. The coil array includes a plurality of coil elements, and each coil element includes a loop of a conductive trace material having at least one capacitive segment.

Description

Technical Field

[0001] (Cross - reference to related applications) This patent application claims the benefit of priority of U.S. Patent Application No. 18 / 119,833, filed on March 10, 2023, which in turn claims the benefit of priority of U.S. Provisional Patent Application No. 63 / 322,069, filed on March 21, 2022, and the disclosures of each are incorporated herein by reference.

[0002] This disclosure relates to magnetic resonance imaging (MRI) guided transcranial focused ultrasound (tFUS) therapy systems and methods, and more particularly to an MRI receive coil array closely integrated with a tFUS treatment transducer device.

Background Art

[0003] High intensity focused ultrasound (HIFU) was proposed and demonstrated as early as 1957 as a method of performing hyperthermia by irradiating ultrasonic energy focused on the target site in the body from outside the body. It can raise the temperature of the target lesion to 60 °C or higher in a few seconds and cause tissue necrosis. Therefore, HIFU is used as one of several thermal ablation methods for various tumors, but was initially applied to the brain for neurological diseases. Compared with other traditional surgeries, HIFU provides a minimally invasive alternative in the outpatient setting with no incisions, no exposure to ionizing radiation, few side effects, and rapid recovery. However, the application of HIFU has not been widely clinically accepted until magnetic resonance imaging (MRI) is used to guide and monitor tissue temperature and the degree of damage.

Summary of the Invention

[0004] Disclosed is a magnetic resonance imaging (MRI) receive coil device for use in an MRI-guided transcranial focused ultrasound (tFUS) system, and a method of manufacturing the same. The described receive coil device is wearable, hydrophobic, and ultrasound transmissive, and includes an MRI receive coil or an MRI receive coil array. In one embodiment, the MRI receive coil device includes a first inner layer of a flexible substrate made of a hydrophobic and ultrasound transmissive thin film, fabricated to fit and conform to a specific three-dimensional (3D) shape such as the head of a subject or an individual patient. A pattern of conductive material can be formed on a first surface of the first inner layer. The pattern may include at least one receive coil and at least one capacitor, and the conductive trace thus formed may include a plurality of conducting layers and at least a layer of dielectric plastic material. A second thin film outer layer of the same material as the first inner layer is formed over the conductive pattern. The three-dimensional (3D) geometric configuration of the receive coil device may conform to the 3D geometric configuration of a head model rendered from a 3D image data set of an individual patient. In an alternative embodiment, the thin film coil device is fabricated based on a fixed 3D shape, and a gel-like ultrasound transmissive material is used to create an individual-shaped thin layer of gel pad lining that conforms to the head of an individual patient on the inside and to the fixed-shaped thin film coil device on the outside. The described method can utilize printing techniques from three dimensions up to a maximum of six dimensions or other precision multi-dimensional manufacturing techniques.

Brief Description of the Drawings

[0005] In this specification, various embodiments are described and illustrated with reference to the following drawings, in which like items are denoted by like reference numerals.

[0006] FIGS. 1A and 1B show an exemplary transcranial focused ultrasound (tFUS) device according to one or more embodiments.

[0007] Figures 2A and 2B show an exemplary thin film coil array assembly with associated tFUS transducers according to one or more embodiments.

[0008] Figure 3 shows an exemplary process for constructing a customized thin film coil array assembly according to one or more embodiments.

[0009] Figure 4 shows an example of a 3D MRI image dataset and its resulting surface rendering according to one or more embodiments.

[0010] Figures 5A, 5B, 5C, and 5D show examples of a 3D printed head mold and a thin film layer fabricated thereon according to one or more embodiments.

[0011] Figure 6 shows a cross-sectional layer view of successive layers of a single coil element of an exemplary coil array according to one or more embodiments.

[0012] Figure 7 shows a top view of an exemplary coil array configuration having adjacent overlapping coil loop elements according to one or more embodiments.

[0013] Figure 8A shows a view of an enclosed end ring for holding an adjustment / matching circuit board according to one or more embodiments.

[0014] Figure 8B shows a typical adjustment / matching circuit board for one channel of an exemplary receive-only coil array element according to one or more embodiments.

[0015] Figure 8C shows an exemplary thin film coil array assembly having an end ring fixed on a coil array cap according to one or more embodiments.

[0016] Figure 8D shows a cross-sectional view of an interface configuration between an end ring and a coil array cap according to one or more embodiments.

[0017] FIG. 9 shows an interface between a customized thin film coil array assembly and a frame of a tFUS transducer device according to one or more embodiments.

[0018] FIG. 10 shows an exemplary process for constructing a universal thin film coil array assembly according to one or more embodiments.

[0019] FIGS. 11A and 11B show an exemplary universal thin film coil array constructed on a fixed shape mold according to one or more embodiments.

[0020] FIG. 12 shows an exemplary concave mold for forming a wearable customized liner according to one or more embodiments.

[0021] FIG. 13 shows an exemplary flow process for placing a universal thin film coil array assembly on a patient's head according to one or more embodiments.

[0022] FIG. 14 shows an interface between a universal thin film coil array assembly and a frame of a tFUS transducer device according to one or more embodiments. DETAILED DESCRIPTION

[0023] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. The present disclosure may be practiced without some or all of these specific details. For the purpose of clarity in explaining the present disclosure, well-known process operations generally practiced in the art are not described in detail so as not to unnecessarily obscure the described concepts. Although some concepts are described in conjunction with specific embodiments, it will be understood that these embodiments are not intended to be limiting. On the contrary, it is intended to cover alternatives, modifications, and equivalents as may be included within the spirit and scope of the present disclosure as defined by the appended claims.

[0024] For example, the techniques of the present disclosure are described in the context of focused ultrasound therapy for various body parts such as the head and brain. However, it should be noted that the techniques and mechanisms of the present disclosure can be applied to various other body parts such as the abdomen or torso. Various techniques and mechanisms of the present disclosure may be described in the singular for clarity. However, some embodiments should be noted to include multiple repetitions of the technique or multiple instantiations of the mechanism, unless otherwise specified.

[0025] (Overview) The advantages of magnetic resonance imaging (MRI) for guiding thermal therapy are not limited to being able to rapidly and accurately image the temperature of the treatment target within the patient's body during ablation therapy. MRI scans, as an imaging modality with the highest proven contrast in most soft tissues, are used for treatment planning, evaluation of treatment results immediately after treatment, and long-term follow-up. Furthermore, MRI can provide various additional contrast mechanisms such as protein denaturation and lesion formation, and can better control the treatment results even during ablation therapy. Another MRI approach, magnetic resonance acoustic radiation force imaging (MR-ARFI), can detect small focal displacements induced by low-power ultrasound pulses. Comprehensive MRI temperature measurements, in combination with other acoustic measurement techniques, have proven to be an ideal imaging modality for guiding and navigating various focused ultrasound (FUS) treatment procedures, including but not limited to high-intensity focused ultrasound (HIFU) ablation therapy.

[0026] MR-guided HIFU devices have been mainly developed for abdominal target sites. In existing methods, a general-purpose MRI-compatible robotic system is utilized to move and operate devices for treatment or diagnosis within the MRI bore. In other methods, a 3-axis motion stage is used to place the HIFU transducer within an unsealed water tank that can be placed on the MRI patient couch. The arc structure can hold the HIFU transducer and enable mechanical motion control up to a maximum of six degrees of freedom while sitting on the patient couch within the bore of an existing MRI system. An MRI receive-only phased array coil can be used to improve the signal-to-noise ratio (SNR) of the MRI. The smaller the coil, the higher the SNR can be obtained with a smaller sensitivity volume, but when comparing the SNR of the same region of interest, an array of multiple small coils shows a better SNR than a single large coil alone. Another advantage of a multi-channel coil array is that it can be used for parallel imaging to speed up MRI scans. For example, a 32-channel head array coil with overlapping loops arranged in a soccer ball pattern can show a higher SNR and a higher acceleration factor in parallel imaging.

[0027] For abdominal HIFU applications under MRI guidance, it is essential to integrate an HIFU transducer device that can be placed in close proximity to the anatomical structure of the treatment target and moved during treatment to focus on continuous ultrasonic irradiation points in the target region of interest, and an MRI receive coil configuration. The N+1 multi-channel configuration is used not only to utilize a hollow loop coil that moves with the transducer HIFU device while allowing ultrasonic beams to pass through without being obstructed, but also functions as an additional parallel imaging channel for a multi-channel (N) coil array that remains in a fixed position.

[0028] However, the aforementioned system is not designed for in-brain applications. In recent years, in transcranial focused ultrasound (tFUS) transducer array configurations, focused ultrasound has been applied to the treatment of various neurological and psychiatric disorders even under MRI navigation. Such a tFUS transducer device is installed on the top of a patient's head and includes a plurality of transducer elements that transmit a plurality of ultrasonic beams through a water bath and transmit them into the skull. In this transcranial configuration, the tight integration of the MRI head coil array and the tFUS transducer device maximizes the MRI capabilities for image navigation such as target setting, positioning, aiming, real-time monitoring and dose control, immediate prognosis, and follow-up observation. Therefore, it is extremely important for the required treatment accuracy. Advanced MRI technology not only plays a crucial role in targeting defective neural circuits to be treated in support of the contrast of soft tissues obtained from normal anatomical structure images, but also temperature measurement and acoustic dose monitoring are also increasingly demanding in terms of speed and sensitivity.

[0029] MRI-guided tFUS was approved by the FDA in 2016 for the treatment of essential tremor and in 2018 for the treatment of Parkinson's disease with tremor as the main symptom. However, during treatment, MRI scans can only be performed with either a large whole-body MRI coil or a simple two-loop MRI coil inserted into the water bath of the tFUS transducer device. A typical multi-channel head coil for MRI has a structure like a helmet itself and cannot be installed simultaneously with the helmet of the tFUS transducer. Therefore, MRI images can be obtained before ultrasonic treatment. However, if the images used for target setting and treatment planning are acquired with a head coil before treatment, the actual head position during treatment where the tFUS transducer is installed may show mis-registration on the images used for the plan. To ensure the accuracy of the treatment target position, a localization frame fixed to the patient's skull is required. Furthermore, once the tFUS is installed, with a body coil or a simple two-loop coil, not only the complete signal-to-noise ratio (SNR) and acceleration performance, but also the MRI sensitivity can no longer be fully realized.

[0030] To minimize the direct interference between the field of view of the coil's magnetic field and the range of the acoustic field from the hemispherical tFUS transducer, a method has been proposed that uses a soft eight-channel coil wrapped around the patient's head and the lower part of the face and placed outside the water bath of the tFUS transducer installed on the top of the head. Since the coil is placed outside the tFUS transducer, in this configuration, it is not possible to fully image a specific substantial part of the brain that can be the treatment target. Furthermore, even if the wire coil shows high acoustic transparency, the material like cloth used to embed the wire coil elements and wrap around the patient's face is air-permeable and thus neither hydrophobic nor ultrasonic-transparent. Therefore, it is not possible to improve the imaging of the treatment target by immersing the coil in the water bath inside the tFUS transducer or placing it inside the tFUS transducer.

[0031] However, by appropriately selecting sufficiently thin layers of a conductive material and a dielectric material for coil manufacturing, the coil can be placed within the tFUS transducer, and the attenuation of the ultrasonic beam passing through the coil trace for the tFUS transducer can be reduced. The present disclosure provides a configuration of a thin film coil array disposed within a tFUS transducer device that improves signal-to-noise ratio (SNR) performance, enables acceleration of parallel imaging, and enables high temporal resolution of navigated MRI scans. The described systems and methods achieve tightly integrating an MRI coil array within a tFUS transducer device while maintaining or meeting the following requirements. An array of 8 to 16 or more MRI signal receiving channels Proximity placement to the head Fixed at a predetermined position with rigidity despite the water bath, ensuring RF reception stability Minimize acoustic attenuation and ensure acoustic beam transmission and proper focusing Minimize interference from the transducer

[0032] Briefly, the described systems and devices can include or implement the following elements. A solid 3D model for providing the external surface shape of the head, constructed from a 3D MRI image of the patient's individual head; A thin film layer made on the head mold from a hydrophobic and acoustically transparent material, including but not limited to TPU (thermoplastic polyurethane), various ultrasonic gel materials, etc.; the manufacturing techniques employed in this step and subsequent steps are 3D or up to 6D printing techniques; A first layer of conductive material made on the thin film to form the base trace of the coil pattern, then a layer of dielectric segments for capacitors, and an overlapping layer of conductive material; A first thin film layer and a second thin film layer made on the conductive material to form a thin film coil array having elasticity, hydrophobicity, and ultrasonic transparency, such as a soft cap; An end ring, which is a solid structure that holds an electrical circuit for a coil element and is attached to seal a conductive material within a thin film coil array cap.

[0033] The manufacturing techniques used for this thin film layer and the conductive material are not the silk screen planar printing commonly used for flexible printed circuit boards on a planar substrate. Instead, high-precision multi-dimensional (from 3D to 6D) printing techniques are employed. The thin film coil array assembly can be placed on a patient's head before being sealed into the frame of the tFUS device.

[0034] In an alternative embodiment, a convex mold is constructed based on a defined 3D shape, a universal thin film coil array is fabricated thereon, and its concave counterpart is used with a head mold to form a void filled with an ultrasonic transmissive gel-like material to create a customized gel pad liner. As another embodiment, a gel material layer of the liner can also be fabricated on top of the head mold and externally conformed to the defined 3D shape of the universal coil array.

[0035] (Exemplary Embodiment) Figures 1A and 1B show an exemplary transcranial FUS (tFUS) device 100 according to one or more embodiments. FIG. 1A is a perspective view of the tFUS device 100 showing the cavity 102 in which the subject's head is placed. The tFUS device 100 further includes a frame 110 with an attachment mechanism 112 for interconnecting with another frame that holds the subject interface membrane. FIG. 1B is a side view of the tFUS device 100 disposed on the head of the subject 130. As described herein, the subjects of the systems and devices described may sometimes be referred to as "patients" or "users". To fully utilize the MRI image navigation capabilities for advanced transcranial focused ultrasound (tFUS) treatment of various neuropsychiatric diseases, especially for real-time monitoring of tissue temperature, degree of necrosis, or the effect of ultrasonic neuromodulation during treatment, optimal performance of the received signal-to-noise ratio (SNR) is becoming increasingly essential for the required spatial and temporal resolutions. This is typically achieved by equipping a clinical MRI system with a dedicated high-frequency (RF) receive coil array for the head. A particular coil array may include up to 32 channels, or more elements or channels for scanning the head and / or brain. However, due to the presence of the tFUS transducer device, tight integration has been difficult from the perspective of the complexity of the mutual compatibility of the two modalities. The described coil array assembly solves such problems regarding the optimal position, stable support, waterproofing, and ultrasonic transparency of the multi-channel coil array with minimal changes to existing tFUS transducer configurations.

[0036] Since the coil needs to be placed close to the head inside the transducer device, the coil array is placed in the path of the ultrasonic beam emitted from the transducer device, and thus, it is often inevitably immersed in the water bath, which is used as an ideal interface medium with the patient's head for the ultrasonic beam emitted from the transducer element. Addressing the related problems has been a significant challenge.

[0037] Referring to FIGS. 2A and 2B, exemplary thin-film coil array assemblies 200-A and 200-B according to one or more embodiments are shown. FIG. 2A shows a wearable thin-film coil array assembly 200-A having a coil array 220-A arranged in a cylindrical configuration. Assembly 200-A may be integrated with a conventional tFUS transducer array 100-A dispersed on a hemispherical surface. As used herein, a thin-film coil array assembly may sometimes be referred to as a "coil array assembly" or an "MRI receive coil device". As shown in FIG. 2A, the coil array assembly 200-A is positioned or worn on the head of a subject 130. In various embodiments, the coil array assembly 200-A includes a thin-film cap 202-A coupled to an end ring 204. In one embodiment, the thin-film cap 202-A includes a coil array 220-A of one or more coil elements (including conductive loops and series capacitors) embedded between two thin-film layers 210-A. In some embodiments, the thin-film layers are made from a selected material such as a thermoplastic. For example, in the form of a thin film, thermoplastic polyurethane (TPU), which is known to exhibit minimal ultrasonic attenuation and high hydrophobicity, may be used. Further, the described systems and methods are not limited to the use of TPU, and other selected materials including polymers and fluoropolymers may be selected based on various properties including elasticity, hydrophobicity, ultrasonic transparency, and good dielectric properties. For example, the thin-film material may include one or more of, but is not limited to, a polyimide (PI) film, a polyethylene (PE) film, a polyethylene terephthalate (PET) film, a polyethylene naphthalate (PEN) film, a polyetherimide (PEI) film, a polyphenylene sulfide (PPS) film, a polytetrafluoroethylene (PTFE) film, and a polyetheretherketone (PEEK) film. In some embodiments, the conductive loops and series capacitors are fabricated between two layers of the thin film, as further described below.

[0038] In an exemplary embodiment, the coil array assembly includes at least eight channels. The number of channels is not limited to eight, and the described coil array assembly may have fewer than eight channels, or more than eight channels (such as four or sixteen channels depending on the particular application). As shown in FIG. 2A, the element loops of the coil array may be arranged in a cylindrical configuration so as to be disposed around the side of the patient's head. This cylindrical configuration can maintain orthogonality between the high-frequency (RF) magnetic field direction and the ultrasonic beam direction as much as possible when the tFUS transducer 100-A (itself and the array of transducer elements) is dispersed in a hemispherical configuration covering the vertex of the head. The transducer 100-A may be enclosed within the tFUS transducer device 100.

[0039] FIG. 2B shows another embodiment of a coil array assembly 200-B having a coil array 220-B that includes element loops arranged in an overlapping configuration within two layers of a thin film 210-B of a thin film cap 202-B. The coil array assembly 200-B also includes an end ring 204 when fully assembled. The coil array assembly 200-B has a hemispherical configuration, which is optimized for MR imaging of the human cortical structure and can be implemented to function with a tFUS transducer array having elements dispersed in a ring shape or cylindrical structure such as the tFUS transducer 100-B. In FIGS. 2A and 2B, the combination of dual modality arrays in a relative configuration orthogonal to each other is a way to minimize interference between the respective fields generated by each. Also, a cylindrical ultrasonic transducer array can generate a finer and sharper acoustic focus profile for a particular application.

[0040] However, as technology progresses to advanced MRI functional and structural studies of cortical regions near the top of the brain, coil arrays with more than 32 channels having a soccer ball-like configuration may show improved sensitivity or acceleration. In this case, some of the element coil loops are in the path of the ultrasonic beam generated by the central transducer element, and minimizing ultrasonic attenuation is one of the important issues to be solved in order to integrate the two modalities. Despite carefully selecting thin film materials and keeping the thickness of the conductive traces and dielectric segments as thin as possible, as an alternative embodiment, a ring-shaped tFUS transducer array with cylindrically symmetrically distributed elements, shown as 200-B in FIG. 2B, is disclosed herein to be paired with a coil array having a hemispherical distribution.

[0041] The described coil array assembly also addresses another important issue of minimizing eddy currents induced by the coil loops on the transducer hemisphere where a conductive electrode surface may exist. To reduce the influence of eddy currents, the common ground electrode plate of the tFUS transducer is cut or grooved into a number of thin radial strips inside the hemispherical transducer array shown as 100-A in FIG. 2A. The radially striated grooves limit the eddy current loops to a narrow area while maintaining the ground of all connected tFUS transducer elements, minimizing the effect. In the case of the ring-shaped tFUS transducer, the ground is grooved in a comb shape (100-B in FIG. 2B) to achieve a similar effect.

[0042] To ensure that there is no or minimal ultrasonic interference, deflection, or attenuation, the thin film coil array assembly, such as the illustrated 200-A, is fabricated to fit snugly and "wear" on the head of an individual subject. In some embodiments, the described coil array assembly, such as 200-B, is placed on a customized gel pad worn on the subject's head or is placed together with a closely fitting gel pad liner attached inside a thin film cap. The customized liner allows for a close fit to the subject's head while maintaining ultrasonic permeability. Further, the coil array assembly must be installed within the tFUS transducer device and immersed in a water bath that serves as an interface medium between the subject's head and the ultrasonic beam emitted from the transducer. Thus, the coil array assembly is required to have hydrophobicity or waterproofness to protect the coil elements from water and other fluids. The present disclosure describes the configuration and manufacturing method of a coil array assembly that is placed in proximity to a patient's head to satisfy, on the one hand, the proximity principle in achieving an optimal SNR and, on the other hand, the requirements of hydrophobicity and ultrasonic permeability.

[0043] (Customized thin film coil array assembly) In some embodiments, the coil array assembly is customized to fit the head of a particular subject. This ensures the closest overall positioning of the coil elements around the target region (i.e., the subject's head). Referring to FIG. 3, an exemplary process for constructing a customized coil array assembly according to one or more embodiments is shown. FIG. 3 is described with reference to FIGS. 4, 5A, 5B, 5C, 5D, 6, 7, 8A, 8B, 8C, 8D, and 9, which show the components in various stages of the configuration and construction of the described coil array assembly.

[0044] In some embodiments, a 3D model of the subject's head is acquired to construct such a customized coil array assembly. For example, in operation 302, a 3D model of the subject's head is constructed. This 3D model is customized to fit the particular head and corresponding geometric configuration of the subject (or patient). Various techniques are implemented to generate the 3D model.

[0045] In one example, the 3D model is rendered using MRI image data. Referring to FIG. 4, an exemplary 3D MRI image data set 410 and its resulting surface rendering 420 according to one or more embodiments are shown. The image data set 410 shows eight axial view images of the entire head of a user such as subject 130, although the data set 410 includes many more additional images. For example, the 3D MRI image data set 410 includes a total of 148 images, each corresponding to a slice that is 1.2 millimeters thick. Using these images, a binary threshold can be used to define MRI null signal areas that include the air cavities of the head region and the regions outside the head. Next, the null signal areas are processed with a "Connected Components Labeling" algorithm. By selecting the largest area, an image of only the outside of the head can be obtained. All images of only the outside of the head are collected from top to bottom, and a surface rendering of the patient's head is obtained by a "marching cube" algorithm. The marching cube algorithm calculates hundreds of thousands of triangles on the head surface and provides the 3D coordinate data of those triangles to generate the surface rendering 420. It should be recognized that various other techniques, including 3D optical scanning, can be implemented to obtain a 3D model rendering of the subject's head.

[0046] Next, the 3D surface rendering 420 is used to generate a physical model that functions as a mold for constructing the coil array assembly. FIGS. 5A, 5B, 5C, and 5D show an exemplary 3D solid head mold 502 and a thin film layer fabricated thereon, according to one or more embodiments. FIG. 5A shows a 3D head mold 502 constructed from 3D coordinate data using a 3D printer. In various embodiments, the head mold 502 is constructed using 3D manufacturing techniques such as stereolithography (SLA), selective laser sintering (SLS), fused deposition modeling (FDM), digital light processing (DLP), multi-jet fusion (MJF), polyjet, direct metal laser sintering (DMLS), and electron beam melting (EBM), but is not limited thereto. The head mold may be constructed from various materials suitable for the above-described manufacturing techniques, such as, for example, polylactic acid (PLA). In some embodiments, the entire head mold is not constructed. Instead, only the relevant portions of the head mold necessary for shaping and constructing the coil array assembly are constructed. Various printing techniques, including stereolithography, are implemented.

[0047] In operation 304, a first thin film layer is constructed on the head mold. FIG. 5B shows the first thin film layer 510 of the coil array assembly constructed on the head mold. The first thin film layer is referred to as the substrate layer or the inner layer. As described above, the first thin film layer 510 includes a hydrophobic and ultrasonic transmissive material such as TPU. In some embodiments, the first substrate layer is fabricated via various techniques including vacuum forming and printing uniformly and with higher dimensional accuracy on the head mold. In other embodiments, the head mold is coated with a layer of substrate material by immersing the head mold in a bath of liquid material and then drying it. In some embodiments, the first thin film layer is coated on the head mold by spraying the material onto the desired portion of the head mold and then drying it. Additional machining may be used to form or shape the material that is immersed or sprayed onto the mold. Thus, the first thin film layer conforms closely to the geometry of the head mold and, by extension, the subject's head.

[0048] Next, in operation 306, a coil array is constructed on the first thin film layer. FIG. 5C shows the coil array 520 constructed on the first thin film layer 510. In some embodiments, the coil array is fabricated on the first thin film layer 510 using conductive ink and a selected dielectric material. The coil array 520 may include one or more conductive material layers for coil traces and one or more dielectric layers for capacitors. In various embodiments, the coil array includes a conductive trace configured in one or more coil elements and a pattern of discrete capacitors. The coil elements may include loops of conductive trace or other configurations. As shown in FIG. 5C, the coil array 520 includes a plurality of overlapping conductive loops, each of which is a coil element. In an exemplary embodiment, the coil array includes eight overlapping coil elements evenly arranged in a cylindrical pattern surrounding the subject's head as shown in FIG. 5C. One coil element 522 of the coil array is schematically shown in dashed lines in FIG. 5C. The configuration of the coil pattern is further described with reference to FIGS. 6 and 7.

[0049] Referring to FIG. 6, a cross-sectional layer diagram of successive layers of a single coil element 600 of an exemplary coil array according to one or more embodiments is shown. In various embodiments, the coil element 600 is an example of the coil element 522 of FIG. 5C. As visualized in FIG. 6, the coil element 600 is made up of at least three layers 610, 620, and 630, with an intermediate layer 620 of dielectric material sandwiched between two layers 610 and 630 of conductive material. A variety of conductive and dielectric materials can be used. For example, the conductive material may include, but is not particularly limited to, silver, copper, graphene, etc. For example, the dielectric material may include, but is not particularly limited to, polytetrafluoroethylene (PTFE), or other ceramic, glass, mica, and plastic materials.

[0050] These three layers of the coil element 600 (conductor traces and distributed series capacitors) are sandwiched between two thin films 510 and 512. In various embodiments, the conductive layer 610 includes a base conductive trace of a loop having one or more gaps at selected positions along the loop. The conductive layer 610 is fabricated on the first thin film layer or the inner thin film layer. The dielectric layer 620 is fabricated on the conductive layer 610. The dielectric layer 620 includes one or more dielectric segments that overlap the positions of the gaps in the layer 610. Subsequently, on the dielectric layer 620, a second conductive layer 630 is fabricated that includes conductor segments that coincide with the dielectric segments.

[0051] For the purpose of minimizing the attenuation of ultrasonic waves passing through the membrane, in an exemplary embodiment, the thickness of a single layer can be 0.02 millimeters (mm) or less for the conductive materials (layers 610 and 630), 0.1 mm or less for the dielectric material (layer 620), and 0.1 mm or less for the thin film layer materials (layers 510 and 512). However, it should be recognized that the thickness of each layer and component is not limited to the described range and may be varied to achieve various conductive or wave transmission characteristics, as well as various structural or mechanical characteristics. For example, the dielectric material may be provided with a thickness exceeding 0.1 mm.

[0052] The described system may employ multi-dimensional printing techniques for manufacturing both the thin film layers and the multiple layers of the coil array on the thin film layer. In this way, the layers are constructed to conform to the 3D shape of the head mold. Different from the solid head mold 502 that can be constructed by conventional 3D printing techniques, each thin film layer (510, 512) and coil array trace (610, 620, 630) is constructed using a multi-dimensional printer such as a 5D or up to 6D printer that can perform three orthogonal translational dimensional motions in conjunction with 2D to 3D rotational motions on a physical 3D mold. This can be achieved by modifying a conventional 3D printer with a fixture for rotation control or by utilizing a 6-axis robotic arm. This ensures that the thickness of layers such as the thin film substrate layer is uniform throughout the layer on the 3D contour of the mold.

[0053] The described manufacturing technique is clearly different from 2-dimensional (2D) planar screen printing techniques and other planar manufacturing techniques that are commonly used to print traces on a thin planar substrate sheet (i.e., a flexible printed circuit board) and fold it into a non-planar shape after printing. Since such a printed circuit board is flexible, it lacks mechanical stability, especially when immersed in a water bath and subjected to water pressure. Also, such a printed circuit board cannot be accurately conformed to the shape of the subject's head.

[0054] As shown in FIG. 6, the coil element 600 includes a loop configuration formed by four curved trace structures 612 within layer 610, on which one or more gaps 614-A and 614-B are designed between the curved trace structures so that the coil electrically resonates at the Larmor frequency of the MRI scanner, and distributed series capacitive elements are arranged. To form these series capacitive elements, segments of overlapping conductor traces (within layer 630) are aligned with each gap to form what corresponds to two capacitors in series with an inductive loop at the location of the gap. As shown, the overlapping trace 632-A (within layer 630) is aligned with gap 614-A, and the dielectric segment 622-A (within layer 620) is positioned between the overlapping trace within layer 630 and the curved trace structure within layer 610. Also, as shown, the overlapping trace 632-B (within layer 630) is aligned with gap 614-B, and the dielectric segment 622-B (within layer 620) is positioned between the overlapping trace within layer 630 and the curved trace structure within layer 610. The capacitance of the distributed capacitive elements required for resonance can be empirically adjusted by the selection and thickness of the dielectric material and the area of the overlapping segments of the overlapping traces.

[0055] In some embodiments, the dimensions of the curved trace structures 612 are the same. In some embodiments, the dimensions of the gaps 614-A and 614-B are the same. In some embodiments, the dielectric segments 622-A and 622-B are the same. In some embodiments, the dimensions of the overlapping traces 632-A and 632-B are the same.

[0056] In an array of multiple coil loop elements, adjacent loops often slightly overlap in order to remove the mutual inductance that can interfere with resonance. FIG. 7 shows a top view of an exemplary coil array configuration having adjacent overlapping coil loop elements according to one or more embodiments. Coil element 600 is shown in FIG. 7 with adjacent coil elements 710 and 730 overlapping coil element 600. Components located on layer 610 are shown in gray, and components located on layer 630 are shown in blue. Thus, the curved structure 612 of coil element 600 is shown in gray, and the overlapping traces 632-A and 632-B are shown in blue. In one embodiment, opposite patterns are printed on adjacent coil elements to form an overlapping configuration. For example, the curved structures (612-C) of coil elements 710 and 730 are located within layer 630 and shown in blue, while the overlapping traces (632-C) of coil elements 710 and 730 are located within layer 610 and shown in gray. The pattern on dielectric layer 620 prints dielectric traces on all capacitive segments described in FIG. 6. The dielectric traces of layer 620 are also fabricated on overlapping segment 760 wherever the conductive traces of adjacent coil elements overlap (shown schematically by the dashed line). The described configuration minimizes the number of layers to three in order to achieve coil resonance without interfering mutual inductive coupling. By minimizing the number of layers, the amount of material used is also reduced, and the structure of the coil array assembly can be made as thin as possible to minimize ultrasonic attenuation.

[0057] Once the coil pattern is constructed on the first thin film layer, a second thin film layer is constructed over the coil element in operation 308 for additional dielectric isolation and waterproofing. FIG. 5D shows the first thin film layer 510 (shown in dashed lines) and the second thin film layer 512 disposed over the coil element, sealing the coil element within the first and second thin film layers to form the thin film coil array cap 550. As used herein, the second thin film layer is referred to as the cover layer or outer layer. The second thin film layer may be fabricated using any of the described construction techniques for fabricating the first thin film layer. In some embodiments, the techniques used to fabricate the first and second thin film layers may be the same or different.

[0058] The second thin film layer is fabricated directly over the first thin film layer and the coil element. In some embodiments, air pockets or gaps between the thin film layer and the coil element are removed or reduced as much as possible. The second thin film layer may comprise the same material as the first thin film layer, although in some embodiments, different materials may be utilized for each thin film layer. In the operations described above, the thin film caps are constructed layer by layer on a physical head mold, although in some embodiments, a physical 3D head mold may not be required. Instead, the thin film layer and the coil array can be constructed based on 3D head rendering data integrated with a 3DCAD (computer-aided design) model.

[0059] In operation 310, an end ring is attached to the thin film layer of the thin film coil array cap 550. In this way, the coil element is completely sealed within the two thin film layers and the end ring. Further, each coil element of the coil array is electrically connected or otherwise coupled to one channel of the signal receiving unit of the MRI system via a tune and match circuit board (TMCB) encapsulated or housed within the end ring. FIG. 8A shows an exemplary end ring 800 that may be implemented in one or more embodiments of the present disclosure. The end ring 800 includes a plurality of TMCBs 810 disposed along the inner circumference of the end ring. As shown, the structure of the end ring 800 is transparent to show eight TMCBs 810 respectively corresponding to the coil elements of the coil array 520. The TMCB is housed within the structure of the end ring 800, which is a rigid hollow ring-shaped structure. Each TMCB is disposed within the structure of the end ring at equal or substantially equal intervals.

[0060] FIG. 8B shows an exemplary tuning and matching circuit board (TMCB) 810 according to one or more embodiments. The TMCB shown in FIG. 8B includes an input connected to one coil element and an output to a preamplifier having a low input impedance. The circuit board includes ceramic capacitors 812, copper strips 814, variable capacitors 821 and 822, PIN diodes 816, and a printed circuit board 830. Examples of circuit boards include flexible circuit boards and FR4 circuit boards. The TMCB resonates in parallel with the loop of the inductive coil element, providing a high impedance to the coil element, thereby reducing the current in the coil element and removing the mutual inductance effect between non-adjacent coil elements. For adjacent coil elements, an overlapping method is used to remove the mutual inductance effect. The PIN diode 816 is used to perform active decoupling to protect the receive-only coil element from the high RF power transmitted from the transmit coil of the MRI system during transmission. In the printed circuit board 830, by adjusting the capacitances of the variable capacitors 821 and 822, the resonance of the electrical circuit can be adjusted to the Larmor frequency of the MRI magnetic field, achieving an optimal pickup of the magnetic resonance signal.

[0061] The magnetic resonance signal picked up by the coil element is amplified by a multi-stage amplifier such as a preamplifier with a low input impedance, an intermediate amplifier, and various gain amplifiers. Then, the signals from each coil element are carried to the receiver channels, and after the magnetic resonance signals are processed by analog-digital sampling and a digital down-converter, they are rearranged to form time-domain data. Finally, the time-domain data is Fourier-transformed to reconstruct the MR imaging. The above MRI signal processing chain can be made independent for each channel.

[0062] The end ring is a lip or edge structure of each thin film layer and is coupled to the thin film cap. FIG. 8C shows an end ring 800 attached to a thin film coil cap 550 that forms a coil array assembly 500 customized to the head of a particular subject. FIG. 8D shows a cross-sectional side view of a coil array assembly according to one or more embodiments. FIG. 8D shows the interface between the end ring 800 and the thin film coil cap 550. In various embodiments, the end ring 800 may be attached to the thin film coil cap 550 with edge structures 530 and 532 extending from thin film layers 510 and 512, respectively. The edge structure may extend around the entire thin film cap to form a flange-like structure. In some embodiments, the edge structure may be constructed with the thin film layer, such as during the execution of operations 304 and 306. In some embodiments, the edge structure may be an extension or part of each thin film layer.

[0063] Each TMCB within the end ring may be electrically coupled to the coil element via an additional conductive trace 850 embedded within a thin film layer extending from a well-fitted coil array. Such conductive traces can be fabricated with the coil elements on the thin film layer in a similar manner. Another terminal of the TCMB is connected to a corresponding low input impedance preamplifier with a half-wavelength, 50Ω impedance coaxial cable, as shown in FIG. 8B.

[0064] In some embodiments, the end ring may be completely sealed to the edge structure to form a watertight seal. In some embodiments, the end ring is tightened against the flexible material of the thin film layer with sufficient pressure to prevent water or other liquid from passing through the interface between the end ring and the edge structure. As a result, the end ring is configured to engage and interface with the tFUS transducer in a completely sealed state with a watertight seal. Thus, water may be contained at least within the cavity formed between the outer thin film layer, the tFUS transducer device, and the end ring. FIG. 9 shows a customized coil array assembly, such as 200-A, with an end ring 800 that interfaces with the tFUS transducer 100. In various embodiments, the attachment mechanism 112 of the transducer 100 can be configured to engage with the end ring 800 to provide a complete seal. Once completely sealed, the cavity 102 within the transducer is completely sealed between the tFUS transducer and the coil array assembly. Thus, a water bath or other liquid may be contained within the cavity 102 without disturbing or interfering with the coil elements or other components of the coil array assembly. The exemplary customized thin film coil array assembly 200-A (or 500) described is wearable and manufactured to conform to a particular patient's head. The coil array assembly 200-A provides the closest fit to minimize ultrasonic attenuation, is mechanically best supported by the head, and meets the MRI requirements of close proximity and multi-channel parallel acceleration. It can also be reused on the same patient for subsequent treatment or follow-up treatment. As another embodiment, the thin film coil array assembly can be manufactured in combination with a customized thin layer of gel pad lining to conform to one or more universally defined shapes.

[0065] (Configuration of Universal Thin Film Coil Array Assembly) In another embodiment, instead of being customized to a particular subject's head, the thin film coil array assembly is fabricated on a fixed mold having a defined geometric shape of one or more sizes so as to fit as closely as possible to a particular subject. This approach to the universal coil array assembly configuration is facilitated by a customized gel pad liner, which is made to fit closely to the subject's head so that no air gap is formed between the subject's head and the thin film coil array cap, and as a result, ultrasonic deflection or reflection is avoided. FIG. 10 shows an exemplary process for constructing a universal coil array assembly according to one or more embodiments. FIG. 10 is described with reference to FIGS. 11A, 11B, 12, 13, and 14 below, which show the components in the various stages of the coil array assembly configuration and construction being described.

[0066] In operation 1002, a convex mold of a defined shape, such as convex mold 1102 shown in FIG. 11A, is constructed. FIG. 11A shows an exemplary convex mold 1102 and a thin film layer fabricated thereon according to one or more embodiments. In this way, the thin film coil array assembly is fabricated to conform to the outer surface of the fixed geometric shape of convex mold 1102. In various embodiments, the convex mold may be constructed together with a concave counterpart (1202) described further below. The defined geometric shape of the convex mold may be small enough to fit within the tFUS transducer device, yet be slightly larger than the size of an average human head. In some cases, the convex mold may be made in additional sizes to accommodate different head sizes. The convex mold may be constructed from various materials, such as polylactic acid (PLA) or other materials suitable for the various 3D printing techniques described herein.

[0067] In operation 1004, a first thin film layer is constructed on the convex mold. Similar to operation 304, a first layer (inner layer) of material is fabricated on the convex mold to form the first thin film layer 1110. As described, such material may include a TPU thin film. Next, in operation 1006, a coil array is constructed on the first thin film layer. The coil array 1120 is shown positioned on the first thin film layer 1110 in FIG. 11A.

[0068] As previously described with reference to operation 306, the coil array may include one or more conductive material layers for coil traces and one or more dielectric layers for distributed capacitors. In various embodiments, the coil pattern includes a conductive trace configured in one or more coil elements and a pattern of distributed capacitors. The coil array 1120 is shown as a configuration of overlapping rows of overlapping circular element loops, similar to that described in FIG. 2B. However, a coil array of conductive elements of various patterns, including but not limited to the cylindrical configuration shown in FIGS. 2A and 5C, may be constructed in operation 1006. Similarly, a customized thin film coil array assembly constructed via method 300 may include a coil array of overlapping element loops as shown in FIG. 11A, as an alternative to the cylindrical configuration shown in FIGS. 5A - 5D.

[0069] As one exemplary embodiment shown in FIG. 11A, the coil array 1120 includes up to 16 elements distributed over a hemispherical configuration positioned to cover or surround the top of the subject's head. There are two rising columns of overlapping elements. However, the number of elements is not limited to 16. Additional columns of overlapping elements may be implemented. The coil pattern of the coil array 1120 may include three layers of conductive trace - dielectric - conductive trace (similar to layers 610, 620, and 630 shown in FIGS. 6 and 7) printed one after another on the first thin - film layer. Similar to FIG. 7, adjacent coil loop elements may also overlap (and may be arranged in different layers) to remove the mutual inductance of the coil array 1120. However, the overlap may repeat itself in more than one direction for an exemplary configuration.

[0070] In operation 1008, to complete the thin - film coil array cap 1150, a second, i.e., outer, thin - film layer is constructed over the coil elements, similar to the first thin - film layer. FIG. 11A shows the second thin - film layer 1112 disposed on the first thin - film layer 1110 (shown in dashed lines) in the lower - left figure. Thus, the coil array may be completely or mostly sealed between the first and second thin - film layers. As described above, the first and second thin - film layers may be constructed by the multi - dimensional printing apparatus described above. Also, as described above, air pockets or gaps between the thin - film layer and the coil elements are excluded or reduced as much as possible.

[0071] Thereafter, the completed thin - film coil array cap can be removed from the convex mold, and an end ring, such as end ring 800, is attached to the thin - film layer of the thin - film coil array cap in operation 1010 as described above with reference to FIG. 8D. The end ring with the internal adjustment / alignment substrate accommodated therein is connected to and sealed with the thin - film coil array cap 1150. FIG. 11B shows the end ring 800 attached to the thin - film coil array cap 1150 forming the coil array assembly 1100.

[0072] The coil array assembly 1100 can be used generically for any user having a head of an appropriate size that fits within the assembly 1100. However, since the universal coil array assembly is constructed to have a configuration corresponding to a mold 1102 of a predefined size and shape, such an assembly may not fit precisely on the head of any particular subject or patient in such a way as to enable proper removal of voids that could deflect the ultrasonic beam or cause skin burns at the location of the voids. Accordingly, the additional structures described herein may be constructed and implemented within such a universal coil array assembly. For example, a personalized lining layer can be constructed and worn on the patient's head or otherwise disposed inside the thin film coil array cap prior to placing the assembly over the patient's head to provide and maintain the closest fit possible without degrading the ultrasonic waves transmitted by the transducer. The construction of the personalized lining layer can potentially be much quicker and more economical than the construction of a personalized thin film coil array cap that includes complex conductive traces. In this way, by creating a personalized lining layer, multiple patients can cost-effectively and efficiently use a single universal thin film coil array assembly with their respective personalized liners.

[0073] In some embodiments, an ultrasonic transmissive gel material is used to fill the void formed between the patient's head mold (502 shown in FIG. 5A) and the inner surface of the concave fixed shape mold (1202 of FIG. 12) to form a semi-rigid thin layer of the personalized gel pad liner 1220 as shown in FIG. 12. Returning to process 1000, additional operations for creating a patient-specific lining layer that fits a particular patient's head and functions as an effective interface between the patient's head and the thin film cap portion of the thin film coil array assembly are described. In operation 1012, a 3D model of the subject's head is constructed. As previously described with reference to operation 302, a physical model (such as mold 502) can be constructed from 3D image data. However, to reduce materials, cost, and manufacturing time, a physical mold may be created using only the relevant portions of the 3D model. In operation 1014, a concave mold is created. FIG. 12 shows an exemplary concave mold 1202 for constructing a personalized lining layer according to one or more embodiments. As shown in FIG. 12, the concave mold 1202 may include a geometric inner surface shape that is the same as the predefined outer shape of the convex mold 1102. In other words, the outer surface of the convex mold 1102 can be seamlessly joined to the inner surface of the concave mold 1202.

[0074] In various embodiments, the concave mold 1202 and the patient-specific head mold 502 are used together to form a customized liner in operation 1016. Since the concave mold 1202 is the counterpart of the convex mold 1102, the inner surface of the mold 1202 needs to exactly correspond to the surface of the convex mold 1102. When the patient-specific head mold is placed inside the fixed-shaped concave mold, a gap is formed. In some embodiments, the head mold 502 may be placed within the concave mold at a specific distance so as to maintain a minimum distance from the surface of the concave mold at any point along the head mold 502. In some embodiments, the head mold 502 may be positioned within the concave mold so as to minimize the distance between all points of the head mold 502 from the surface of the concave mold while maintaining the minimum distance requirement. In some embodiments, marks on the head mold may be devised to align the molds.

[0075] The customized liner may be formed by filling the gap with an ultrasonic transmissive material that cures to a flexible or semi-rigid structure. For example, a selected ultrasonic gel material can be filled into the gap and formed into a thin semi-rigid gel pad, i.e., the customized liner 1220. In various embodiments, the material can be cured at room temperature or with heat. Once the customized liner is formed, as shown in FIG. 12, the head mold 502 can be removed to enable removal of the customized liner. Once formed, the customized liner should include an outer surface corresponding to the inner surface of the mold 1202 and an inner surface corresponding to the surface of the head mold. Some additional machining may be performed to shape or finish the customized liner.

[0076] Another way to manufacture a customized liner is to build the liner layer directly on the head mold. For example, the head mold can be coated with the liner material so that the inner surface of the liner conforms to the shape of the head mold. Thereafter, the excess liner material may be shaped or machined so that the outer surface conforms to the shape of the universal thin film coil array cap. As another example, the liner material may be printed directly onto the head mold in 3D or higher dimensions so as to have the required external geometry. In some embodiments, during manufacture, an additional thin film layer may be implemented to provide more structural support to the liner layer. For example, an inner thin film layer such as TPU may first be built on the head mold in the same manner as the first thin film layer. Next, the liner material may be built on the inner thin film layer as described above. In certain embodiments, an additional outer thin film layer may be built on the formed liner layer to seal the liner layer within the inner and outer thin film layers.

[0077] In operation 1020, the customized liner is attached to the coil array assembly. FIG. 13 shows an exemplary flow process for positioning a universal thin film coil array assembly on a patient's head according to one or more embodiments. In some embodiments, as shown in FIG. 13, the customized liner is first positioned or worn on the patient's head 130. The universal thin film coil array assembly 1100 can then be positioned on the outer surface of the liner having a complementary geometric profile. However, in some embodiments, the customized liner may first be joined to the inner surface of the first (inner) thin film layer of the coil array assembly 1100 before being positioned on the subject's head. In some embodiments, the customized liner may be fixed and / or sealed with the assembly by an end ring. Thus, the universal thin film coil array assembly can be used for multiple patients, each patient having their own customized liner as a consumable.

[0078] Referring to FIG. 14, an interface between a universal thin film coil array 1100 and the frame of the tFUS transducer device 100 according to one or more embodiments is shown. In some embodiments, the assembly 1100 can alternatively be joined to a tFUS transducer having a transducer array distributed in a ring-shaped structure (as described with respect to transducer 100-B of FIG. 2B) to minimize interference with a particular configuration of the coil elements of the assembly 1100. In various embodiments, the mounting mechanism 112 of the transducer 100 may be configured to be fully sealed on the end ring 800. Once fully sealed, the cavity 102 within the transducer is completely sealed between the tFUS transducer and the coil array assembly. Thus, a water bath or other liquid can be included within the cavity 102 without disturbing or interfering with the coil elements or other components of the coil array assembly.

[0079] (Conclusion) The present disclosure is not limited by the design of the coil array, the number of coil elements or loops, the shape or trace of the loops, or their spatial distribution. The 8-channel array shown in FIG. 8C and the 16-channel array shown in FIG. 11B are merely examples of possible configurations. One of the main considerations in the tight integration of the head coil array and the tFUS transducer device is the mutual interference between the two modalities. Thus, one simple principle is to maintain the orthogonality of the two fields (the ultrasonic field in the direction of the beam and the magnetic field perpendicular to the coil loop). Conventional tFUS transducer arrays are composed of hundreds of transducer elements and are generally distributed on a hemispherical shell. Therefore, the ideal placement of the coil loop is to place the loop along the side of the cylinder, as shown in the configuration of FIG. 2A and the example shown in FIG. 5C.

[0080] The different embodiments of the devices and methods disclosed herein include various components, features, and functions. The various embodiments of the devices and methods disclosed herein may include any combination of the components, features, and functions of other embodiments of the devices and methods disclosed herein, and it should be understood that all possible variations are intended to be within the spirit and scope of the present disclosure. Many modifications of the embodiments described herein will occur to those skilled in the art to which this disclosure pertains, having the benefit of the teachings presented in the foregoing description and the related drawings.

[0081] Accordingly, it is to be understood that the present disclosure is not limited to the specific embodiments illustrated, and that modifications and other embodiments are intended to be included within the scope of the appended claims. Further, although the foregoing description and the related drawings illustrate embodiments of the present disclosure in the context of specific exemplary combinations of elements and / or functions, it should be understood that different combinations of elements and / or functions may be provided by alternative implementations without departing from the scope of the appended claims. Thus, the bracketed reference numbers in the appended claims are presented for purposes of illustration only and are not intended to limit the scope of the claimed subject matter to the specific embodiments provided in the present disclosure.

Claims

1. A thin film substrate layer configured in a dome shape, A coil array disposed around the outer surface of the thin film substrate layer, The thin film cover layer disposed on the outer surface of the thin film substrate layer such that the coil array is disposed between the thin film cover layer and the thin film substrate layer, An end ring engaging with the thin film substrate layer and the thin film cover layer, wherein a watertight seal is formed around the coil array between the thin film substrate layer, the thin film cover layer, and the end ring. A magnetic resonance imaging (MRI) receiving coil device, characterized in that.

2. The dome shape conforms to the geometric profile of the head of a specific subject. The MRI receiving coil device according to claim 1.

3. The dome shape conforms to a predetermined geometric profile. The MRI receiving coil device according to claim 1.

4. The MRI receiving coil device further includes a lining layer configured to conform to the geometric profile of the head of a specific subject. The MRI receiving coil device according to claim 3.

5. The thin film substrate layer or the thin film cover layer includes thermoplastic polyurethane. The MRI receiving coil device according to claim 1.

6. The thin film substrate layer has a thickness of 0.1 millimeter or less. The MRI receiving coil device according to claim 1.

7. The coil array includes a plurality of coil elements, and each of the coil elements includes a loop of conductive trace material having at least one capacitive segment. The MRI receiving coil device according to claim 1.

8. Adjacent coil elements overlap with overlapping segments, and the coil array further includes a dielectric trace disposed within the overlapping segments to electrically insulate adjacent coil elements. The MRI receiving coil device according to claim 7.

9. The coil array is A first layer of conductive material formed on the outer surface of the thin film substrate layer, and the first layer has a first pattern, On the first layer, a second layer of conductive material on the outer surface of the thin film substrate layer, and the second layer has a second pattern, and the first pattern and the second pattern overlap with the overlapping segments and the capacitive segments. The overlapping segments and the capacitive segments, and a layer of dielectric material disposed between the first layer and the second layer, wherein a portion of the overlapping segments forms one or more capacitors, the MRI receiving coil device according to claim 8.

10. The conductive material includes a conductive ink, and the conductive ink includes one or more of gold, copper, silver, graphene, and metal flakes, the MRI receiving coil device according to claim 8.

11. A method of constructing a magnetic resonance imaging (MRI) receiving coil device, the method comprising: Producing a thin film substrate layer on a mold having a dome shape; Producing a coil array around the outer surface of the thin film substrate layer; Producing the thin film cover layer disposed on the outer surface of the thin film substrate layer such that the coil array is disposed between the thin film cover layer and the thin film substrate layer; Engaging an end ring with the thin film substrate layer and the thin film cover layer to form a watertight seal around the coil array between the thin film substrate layer, the thin film cover layer, and the end ring.

12. The method according to claim 11, further comprising forming the dome shape to conform to the geometric profile of the head of a specific patient.

13. The method according to claim 11, further comprising forming the dome shape to conform to a predetermined geometric profile.

14. The method according to claim 13, further comprising configuring a lining layer of the MRI receiving coil device to conform to the geometric profile of the head of a specific patient.

15. The method according to claim 11, wherein the thin film substrate layer or the thin film cover layer is produced as a thermoplastic polyurethane layer.

16. The step of producing the thin film substrate layer includes producing the thin film substrate layer to have a thickness of 0.1 millimeter or less, the method according to claim 11.

17. The step of producing the coil array further includes producing a plurality of coil elements, each coil element including a loop of conductive trace material having at least one capacitive segment, the method according to claim 11.

18. The step of fabricating the coil array includes the step of overlapping adjacent coil elements with overlapping segments, and the step of positioning dielectric traces within the overlapping segments to electrically insulate the adjacent coil elements, the method according to claim 17.

19. The step of fabricating the coil array includes the step of fabricating a first layer of conductive material on the outer surface of the thin film substrate layer, the first layer having a first pattern, the step of fabricating a second layer of conductive material on the outer surface of the thin film substrate layer over the first layer, the second layer having a second pattern, the first pattern and the second pattern overlapping at the overlapping segments and the capacitive segments, the step of fabricating a layer of dielectric material between the first layer and the second layer at the overlapping segments and the capacitive segments, a part of the overlapping segments forming one or more capacitors, the method according to claim 18.

20. A system comprising a transcranial focused ultrasound (tFUS) transducer device including a plurality of transducer elements for transmitting a plurality of ultrasonic beams, and a magnetic resonance imaging (MRI) receive coil device, wherein the MRI receive coil device has a thin film substrate layer with a coil array, the coil array being disposed on the outer surface of the thin film substrate layer and covered with a thin film cover layer, including an end ring engaging the thin film substrate layer and the thin film cover layer, a watertight seal being formed around the coil array between the thin film substrate layer, the thin film cover layer, and the end ring, the coil array being electrically connected to an MRI receiver to transmit received signals via an adjustment and alignment circuit board (TMCB) enclosed by the end ring, the MRI receive coil device being configured to fit closely and airtightly to a subject's head, the transcranial focused ultrasound (tFUS) transducer device being configured to seal the MRI receive coil device in a watertight fit therein. The system is configured to simultaneously operate the MRI receiving coil device and the tFUS transducer device to provide real-time image navigation including target setting, positioning, aiming setting, real-time dose monitoring, and operation control of a tFUS treatment procedure. A system characterized by this.

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