Radio frequency receive coil network for single-sided magnetic resonance imaging

Abstract

A permanent magnet, wherein a Z-axis is defined in the field of view through the permanent magnet.SOLUTION: The single-sided magnetic imaging apparatus further includes an electromagnet, a set of gradient coils, a radio frequency transmit coil, a radio frequency receive coil, and a power supply. The power source is configured to generate an electromagnetic field within the field of view along the Z-axis. The electromagnetic field includes a field gradient within the field of view, and the adjustment of the radio frequency transmit coil is configured to target a location within the field gradient within the field of view.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 62 / 979,332, filed February 20, 2020, entitled "SYSTEM AND METHOD FOR UTILIZING RADIO FREQUENCY RECEIVE NETWORK FOR SINGLE-SIDED MAGNETIC RESONANCE IMAGING," the entire disclosure of which is incorporated herein by reference. [Background technology]

[0002] Magnetic resonance imaging (MRI) systems have primarily focused on the impact of an enclosed form factor. This form factor involves enclosing the imaging region with electromagnetic field-generating materials and imaging system components. A typical MRI system includes a cylindrical bore magnet, with the patient positioned within the magnet's tube for imaging. Components such as radio frequency (RF) transmit coils (TX) and receive coils (RX) are then positioned on many sides of the patient, effectively surrounding the patient for imaging.

[0003] Typically, the RF-TX coil is large and completely surrounds the field of view (i.e., the imaging region), while the RF-RX coil is small and placed directly above the field of view. In various existing MRI systems, these and other components substantially surround the patient, and their placement significantly restricts patient movement. The positioning of the RF-TX and / or RF-RX coils relative to the patient can cause additional strain during patient placement in and / or removal from the imaging region. For example, RF-RX coils are often placed directly on the patient before inserting the patient into the imaging bore of the magnet. These coils can suppress patient movement, resulting in acquisition of only specific orientations of the patient and the coil relative to the patient. In other MRI systems, the patient is placed between two large plates to alleviate some physical restrictions on patient positioning. Regardless, there is a need to provide advanced imaging configurations for next-generation MRI systems that further alleviate the aforementioned problems related to patient comfort and burdensome positional restrictions. Summary of the Invention

[0004] In one general aspect, the present disclosure provides a single-sided magnetic imaging device including a permanent magnet, the Z-axis of which is defined to extend perpendicular to the permanent magnet within a field of view and configured to generate a static magnetic field in the Z-axis. The single-sided magnetic imaging device further includes a radio frequency transmit coil configured to generate an electromagnetic field within a target and a variably tuned radio frequency receive coil configured to detect magnetic flux within the target responsive to the electromagnetic field. A power source is configured to generate the electromagnetic field within the field of view along the Z-axis. The variably tuned radio frequency receive coil is further configured to be tuned to multiple frequencies to match the frequency of the electromagnetic field at a location.

[0005] In another aspect, the present disclosure provides a method of calibrating a single-sided magnetic imaging device, the method including generating a static magnetic field in the Z-axis with a permanent magnet, generating an electromagnetic field in a region of interest with a radio frequency transmit coil, and adjusting parameters of a radio frequency receive coil to target an imaging location within the field gradient of the electromagnetic field. [Brief explanation of the drawings]

[0006] The novel features of the various aspects are set forth with particularity in the appended claims, but the described aspects, both as to organization and method of operation, can best be understood by reference to the following description taken in conjunction with the accompanying drawings.

[0007] [Figure 1] FIG. 1 is a schematic diagram of a magnetic resonance imaging system according to various aspects of the present disclosure.

[0008] [Figure 2] FIG. 2 is an exploded perspective view of the magnetic resonance imaging system shown in FIG. 1 according to various aspects of the present disclosure.

[0009] [Figure 3] FIG. 3 is an elevational view of the magnetic resonance imaging system shown in FIG. 1 according to various aspects of the present disclosure.

[0010] [Figure 4] FIG. 4 is an elevational view of the magnetic resonance imaging system shown in FIG. 1 according to various aspects of the present disclosure.

[0011] [Figure 5] FIG. 5 is an exemplary positioning of a patient for imaging by a magnetic resonance imaging system for certain surgical operations and procedures, according to various aspects of the present disclosure.

[0012] [Figure 6] FIG. 6 is an exemplary schematic diagram of an RF-RX array including individual coil elements and a variable magnetic field, according to various embodiments of the present disclosure.

[0013] [Figure 7] FIG. 7 is an exemplary diagram of a loop coil along with exemplary variables of the loop coil magnetic field, according to various aspects of the disclosure.

[0014] [Figure 8] FIG. 8 is an exemplary XY chart showing the magnetic field as a function of the radius of a loop coil, according to various embodiments of the present disclosure.

[0015] [Figure 9] FIG. 9 is a cross-sectional view of a portion of a human body including the area around the prostate gland, according to various embodiments of the present disclosure.

[0016] [Figure 10] FIG. 10 is an elevation view of an RF-RX array in a housing, according to various embodiments of the present disclosure, showing the housing as a transparent component for illustrative purposes to expose the individual coil elements within the housing.

[0017] [Figure 11] FIG. 11 is another elevational view of the RF-RX array of FIG. 10 according to various embodiments of the present disclosure.

[0018] [Figure 12] FIG. 12 is a perspective view of the RF-RX array of FIG. 10 according to various aspects of the disclosure.

[0019] The accompanying drawings are not intended to be drawn to scale. Corresponding reference characters indicate corresponding parts throughout the several views. For clarity, not every component is shown in every drawing. The illustrations set forth herein illustrate some embodiments of the present invention in one form, and such illustrations should not be construed as limiting the scope of the present invention in any way. DETAILED DESCRIPTION OF THE INVENTION

[0020] The following international patent applications are incorporated herein by reference in their entirety: International application PCT / US2020 / 018352, filed February 14, 2020, entitled "SYSTEMS AND METHODS FOR ULTRALOW FIELD RELAXATION DISPERSION," now published internationally as WO2020 / 168233 International application PCT / US2020 / 019530, filed February 24, 2020, entitled "SYSTEMS AND METHODS FOR PERFORMING MAGNETIC RESONANCE IMAGING," now published internationally as WO2020 / 172673 International application PCT / US2020 / 019524, filed February 24, 2020, entitled "Pseudo-Birdcage Coil with Variable Tuning and Applications Thereof," now published as WO2020 / 172672 International application PCT / US2020 / 024776, filed March 25, 2020, entitled "SINGLE-SIDED FAST MRI GRADIENT FIELD COILS AND APPLICATIONS THEREOF," now published as WO2020 / 198395 International application PCT / US2020 / 024778, filed March 25, 2020, entitled "SYSTEMS AND METHODS FOR VOLUMETRIC ACQUISITION IN A SINGLE-SIDED MRI SYSTEM," now published as WO2020 / 198396 International application PCT / US2020 / 039667, filed June 25, 2020, entitled "SYSTEMS AND METHODS FOR IMAGE RECONSTRUCTIONS IN MAGNETIC RESONANCE IMAGING," now published as WO2020 / 264194 · International application PCT / US2021 / 014628, filed January 22, 2021, entitled "MRI-GUIDED ROBOTIC SYSTEMS AND METHODS FOR BIOPSY"

[0021] U.S. Patent Application Publication No. 16 / 003,585, published June 8, 2018, entitled "UNILATERAL MAGNETIC RESONANCE IMAGING SYSTEM WITH APERTURE FOR INTERVENTIONS AND METHODOLOGIES FOR OPERATING SAME," is hereby incorporated by reference in its entirety.

[0022] The following US provisional patent applications are incorporated herein by reference in their entireties: U.S. Provisional Patent Application No. 62 / 987,286, filed March 9, 2020, entitled "SYSTEMS AND METHODS FOR ADAPTING DRIVEN EQUILIBRIUM FOURIER TRANSFORM FOR SINGLE-SIDED MRI" U.S. Provisional Patent Application No. 62 / 987,292, filed March 9, 2020, entitled "SYSTEMS AND METHODS FOR LIMITING K-SPACE TRUNCATION IN A SINGLE-SIDED MRI SCANNER"

[0023] Before describing various aspects of the MRI system and method in detail, it should be noted that the exemplary embodiments are not limited in application or use to the details of construction and arrangement of parts illustrated in the accompanying drawings and description. The exemplary embodiments may be implemented or incorporated with other embodiments, variations, and modifications, and may be practiced or carried out in various ways. Furthermore, unless otherwise specified, the terms and phrases used herein have been chosen for the convenience of the reader and for the purpose of describing the exemplary embodiments, and not for the purpose of limiting them. It will also be understood that one or more of the following described aspects, embodiment expressions, and / or examples can be combined with any one or more of the other following described aspects, embodiment expressions, and / or examples.

[0024] A typical MRI system creates a uniform field within the imaging region. This uniform field then generates a narrow band of magnetic resonance frequencies that can be captured by a receive coil (RF-RX), amplified, and digitized by a spectrometer. Because the frequencies are within a narrow, well-defined bandwidth, hardware architectures have focused on creating statically tuned RF-RX coils with optimal coil quality factors. Many variations of coil architectures have been created, exploring large single-volume coils, coil arrays, parallel coil arrays, or object-specific coil arrays. However, these structures are premised on imaging specific frequencies close to interest at high field strengths and are as small as possible to fit within the enclosed MRI machine's magnetic bore or tube.

[0025] According to various aspects, an MRI system is provided that can include a unique imaging region that can be offset from the plane of the magnet. Such offset and single-sided MRI systems are less restrictive than conventional MRI scanners. Furthermore, this form factor can have built-in or inherent magnetic field gradients that create a wide range of magnetic field values ​​throughout the region of interest. Furthermore, this system can operate at lower magnetic field strengths compared to typical MRI systems, thereby relaxing RX coil design constraints and / or allowing additional mechanisms, such as robotics, to be used in the MRI scanner. Exemplary MRI-guided robotic systems are further described, for example, in International Application PCT / US2021 / 014628, filed January 22, 2021, entitled "MRI-GUIDED ROBOTIC SYSTEMS AND METHODS FOR BIOPSY."

[0026] The unique architecture of the main magnetic field of an MRI system according to various aspects of the present disclosure can create a different set of optimization constraints. Because the imaging volume spans a wider range of magnetic resonance frequencies, hardware can be configured to be sensitive to and capture specific frequencies generated across the field of view. This frequency spread is typically much greater than what a single receive coil tuned to a single frequency can sense. Furthermore, because the field strength can be much lower than in conventional systems and signal strength can be proportional to the field strength, it is generally considered beneficial to maximize the signal-to-noise ratio (SNR) of the receive coil network. Thus, according to various aspects, a method is provided for acquiring the full range of frequencies generated within the field of view without loss of sensitivity.

[0027] 1-5 illustrate a magnetic resonance imaging system 100. As shown in FIGS. 1 and 2, the magnetic resonance imaging system 100 includes a housing 120. The housing 120 includes a front surface 125. According to various embodiments, the front surface 125 may be a concave and / or recessed front surface.

[0028] As shown in FIGS. 1 and 2 , the housing 120 includes a permanent magnet 130, a radio frequency transmit coil 140, a gradient coil set 150, an electromagnet 160, and a radio frequency receive coil 170. As shown in FIGS. 3 and 4 , the permanent magnet 130 may include multiple magnets arranged in an array configuration. The multiple magnets forming the permanent magnet 130 may cover the entire surface, as shown in the front view of FIG. 3 , or may be configured as horizontal bars, as shown in the side view of FIG. 4 . Referring primarily to FIG. 1 , the main permanent magnet array may include at least one access opening or bore 135, which allows access to the patient through the housing 120 from the opposite side of the housing 120. In other aspects of the present disclosure, the array of permanent magnets may be boreless and may define an uninterrupted arrangement of permanent magnets without a bore defined therethrough.

[0029] According to various aspects of the present disclosure, the permanent magnet 130 provides a static magnetic field within the region of interest 190. According to various embodiments, the permanent magnet 130 may include multiple cylindrical permanent magnets in a parallel configuration, as shown in Figures 3 and 4. For example, the permanent magnet assembly 130 may include any suitable magnetic material, including, but not limited to, rare earth-based magnetic materials such as neodymium-based magnetic materials.

[0030] According to various embodiments using the magnetic resonance imaging system 100 illustrated in Figures 1-4, the patient can be positioned in any number of different positions depending on the type of anatomical scan. As an example, as shown in Figure 5, when the pelvis is scanned with the magnetic resonance imaging system 100, the patient can be positioned on a surface in a lithotomy position. As illustrated in Figure 5, for a pelvic scan, the patient can be positioned with their back on the table and their legs elevated and resting on top of the system 100. The pelvic region can be positioned just anterior to the bore 135.

[0031] According to various aspects, several methods are provided that can enable imaging within the MRI system 100. These methods can include combining one or more of variably tuned RF-RX coils, RF-RX coil arrays with elements tuned to frequencies that depend on the spatial inhomogeneity of the magnetic field, ultra-low noise preamplifier designs, and RF-RX arrays with multiple receive coils designed to optimize signal from a defined and limited field of view for a particular object portion. These methods can be combined in any combination as needed.

[0032] In various aspects of the present disclosure, a variable tuning RF-RX coil may be incorporated into the MRI system 100. For example, the radio frequency receive coil 170 may include a variable rotation RF-RX coil. The variable rotation RF-RX coil may include one or more electronic components for tuning the electromagnetic receive field. In various implementations, the one or more electronic components may include at least one of a varactor, a PIN diode, a capacitor, an inductor, a MEMS switch, a solid-state relay, or a mechanical relay. In various implementations, the one or more electronic components used for tuning may include at least one of a dielectric, a capacitor, an inductor, a conductive metal, a metamaterial, or a magnetic metal. In various implementations, tuning the electromagnetic receive field can be achieved using different methods, such as a voltage tuning method that changes voltage to activate components, or a physical relocation method that changes the physical location of one or more electronic components, thereby tuning their capacitance or inductance characteristics.

[0033] The voltage adjustment method involves using a passive device with switching capabilities. The most commonly used device for this purpose is a PIN diode. By applying a forward voltage, the PIN diode becomes forward biased, meaning that it turns on, thereby allowing current to pass to the connected device. This method can be useful for selectively turning on coils by sending a forward voltage to the coil to be used. However, the disadvantages of this method are that PIN diodes are quite expensive compared to the cost of the actual receive coil and are prone to damage during transmission due to voltage spikes from the TX coil. The physical repositioning method requires physically moving the coil to change its inductive and capacitive characteristics. Because this process involves physical movement of the coil, it can, in certain instances, cause additional strain on the patient during scanning. Both methods adjust the intrinsic resonant frequency or coil bandwidth.

[0034] In various implementations, the coil is cryogenically cooled to reduce resistance and improve efficiency.

[0035] In various aspects of the present disclosure, the MRI system 100 may include an RF-RX array that includes individual coil elements that are tuned to different frequencies. The appropriate frequencies may be selected, for example, to match the frequency of the magnetic field located at the particular spatial location where the particular coil is located.

[0036] Referring now to the schematic diagram 300 of FIG. 6, an RF-RX array 308 and a magnetic field 310 are shown. The magnetic field 310 can vary as a function of space, and the magnetic fields and frequencies of the coils 302, 304, and 306 of the RF-RX array 308 can be adjusted to approximately match spatial locations. Here, the coils 302, 304, and 306 can be designed to image field locations B1, B2, and B3 that are physically separated along a single axis B0 in the Z direction. In FIG. 6, the coils 302, 304, and 306 overlap with adjacent coils, as shown by the ellipses crossing each other.

[0037] 6 may be incorporated into the magnetic imaging system 100. For example, the radio frequency receive coil 170 may further include an RF-RX array that is adjustable along the Z-axis.

[0038] For a low-field system such as system 100, for example, a low-noise preamplifier can be designed and configured to take advantage of the low-signal environment of an MRI system. This low-noise amplifier can be configured to utilize components that do not generate significant electronic or voltage noise at the desired frequencies (e.g., <4 MHz and >2 MHz). If there is an input signal to the preamplifier, the signal and noise are amplified by the preamplifier by the same amount (gain). To obtain useful low-noise amplification, the signal amplitude must be high while maintaining low noise. To keep noise to a minimum, the preamplifier's SNR must be high. One way to achieve a good SNR while keeping noise levels low is to add an operational amplifier (op-amp) in parallel. Typical junction field-effect transistor designs (J-FETs) generally do not have adequate noise characteristics at this frequency and, while tens of dB lower, can produce high-frequency instabilities in the GHz range that can bleed into the measured frequency range. The system's gain is preferably, for example, >80 dB overall, amplifying any small instabilities or inherent electrical noise and degrading signal integrity.

[0039] In various aspects of the present disclosure, an RF-RX coil can be designed to image a specific, limited field of view based on the target anatomical structure. For example, referring to diagram 600 in FIG. 9, the prostate is approximately 60 millimeters deep within the human body. To design an RF-RX coil for prostate imaging, the coil must be configured to enable imaging at a depth of 60 mm within the human body. Referring to the variables and coil schematic 500 in FIG. 7, according to the Biot-Savart method, the magnetic field of the loop coil can be calculated by the following equation:

number

[0040] A low-impedance preamplifier design with an input impedance of less than 5 ohms can be used in series with the matching network of a coil in a receive coil array to provide active decoupling from adjacent coils in the same array. This technique does not rely on geometric decoupling to cancel mutual conductance between coils, but allows individual coils in the array to be decoupled from each other using the low-noise preamplifier itself. Each coil in a receive coil array has an inductive and capacitive matching network used to match the coil's resistance to 50 ohms for maximum power transfer. When a low-impedance preamplifier is connected to the coil's matching network, the low impedance acts as a short, thereby making the impedance seen by the coil infinite and trapping any coil current.

[0041] Due to the geometric constraints of the body, loop coils can be placed in the space between a person's legs on the torso. Therefore, fitting a 170 mm diameter coil in that location would be extremely difficult, if not impossible. According to Figure 8, when R is less than 85 mm, the Bz field value increases with the radius of the loop. Therefore, it is advantageous to make the coil as large as possible. For example, the largest loop coil that can be placed between a person's legs is approximately 10 cm in diameter.

[0042] Because the size of the coil may generally be limited by the space between a person's legs, for example, the magnetic field of a 10 cm diameter coil generally cannot reach the depth of the prostate. Therefore, for example, a single coil may not be sufficient to image the prostate. Therefore, in this case, multiple coils may prove beneficial to acquire signals from different directions. In various embodiments of MRI systems, the magnetic field is provided in the z direction, and the RF coil is sensitive to the x and y directions. In this exemplary case, a loop coil in the xy plane cannot collect RF signals from the person because it is sensitive in the z direction, but a butterfly coil can be used in this case. Then, based on the location and orientation, the RF coil can be a loop coil or a butterfly coil. Furthermore, the coil can be placed under the body, and there is no limit to its size. Figures 10-12 illustrate an RF array 700, further described herein and including, for example, a combination of different types of coils.

[0043] For the need for multiple RX coils, in various aspects of the present disclosure, isolation between them may prove beneficial to various aspects of the MRI system RX coil array. In these cases, each coil may be isolated from the other coils, and isolation techniques may include, for example, 1) geometric isolation, 2) capacitive / inductive decoupling, and 3) low / high impedance preamplifier coupling.

[0044] Geometric decoupling may be the simplest decoupling technique because it does not involve any active or passive circuit elements to achieve the required decoupling. Each coil in a receive coil array is a transmitting wire, meaning that each coil has its own self-induction and mutual induction. When a receive coil is excited with a voltage, it generates a magnetic field that is effectively "visible" to any coils adjacent to it, which in turn generates noise. To reduce this effect, the coils are geometrically arranged to minimize the mutual conductance between them. The disadvantage of this method is that the coils are constrained by their geometry, and any additional movement or manipulation of the coil geometry (e.g., by bending) changes the coil conductance and mutual conductance, leading to changes in decoupling.

[0045] According to various embodiments, the MRI system can have a varying magnetic field from the magnet, the strength of which can vary linearly along the z-direction. The RX coils can be positioned at different positions in the z-direction, and each coil can be tuned to a different frequency, which can depend on the coil's location within the system.

[0046] Based on the simplicity of a single coil loop, these coils can be constructed from simple conductive traces that can be pre-tuned to the desired frequency and printed, for example, on a disposable substrate. This inexpensively fabricated technology allows clinicians to place an RX coil (or coil array) on the body at the region of interest for a given procedure and then discard the coil. These coils can be constructed, for example, from 3D-printed copper, silver, or other conductive inks on plastic or woven fabric materials. Alternatively, conductive wire can be woven into the fabric to create a coil that is resistant to deformation. For example, an RX coil can be a surface coil that can be worn or taped to the patient's body. For certain body parts, such as the ankle or wrist, the surface coil can be a single loop, a figure-eight design, or a butterfly coil wrapped around the region of interest. For areas requiring significant penetration depth, such as the torso or knee, the coil can consist of a Helmholtz coil pair. Like the receive coils in other MRI systems, the coil is optimally sensitive in a plane perpendicular to the main magnetic field B0 of the axis in Figure 6.

[0047] In some instances, the coil may be inductively coupled to another loop that is electrically connected to a receive preamplifier. This design may allow for easier and unobstructed access to the receive coil. Receive coils from other MRI systems may have a preamplifier on the coil to reduce any signal loss due to cable loss, insertion loss, etc. This also means that the preamplifier is near or adjacent to the patient, thereby creating an electrical hazard. By moving the receive preamplifier away from the receive coil, the patient may have unobstructed access to the receive coil in various aspects of the present disclosure.

[0048] According to various aspects of the present disclosure, the size of the coil may be limited by the structure of the human body, for example, the size of the coil should be positioned and configured to fit in the space between a person's legs when imaging the prostate.

[0049] 10-12, an RF-RX array 700 is shown. The RF-RX array 700 is positioned within a housing or enclosure 702 that houses the different coils that make up the RF-RX array 700. In the exemplary embodiment shown in FIGS. 10-12, the RF-RX array 700 includes five coils 704, 706, 708, 710, and 712. The coils 704, 706, 708, 710, and 712 are butterfly coils that include a pair of lobes. The first coil 704 forms a first lobe or loop at the top of the array and a second lobe or loop at the center of the array. The first loop of the first coil 704 surrounds the second coil 706. The second loop of the first coil 704 surrounds a through-hole 714 in the enclosure 702. The second coil 706 is located above the through-hole 714. The third coil 708 extends around the upper half of the through-hole 714. The fourth coil 710 extends around the lower half of the through-hole 714. The loop ends of the third and fourth coils 708, 710 overlap at a vertical centerline through the through-hole 714. The first coil 704 also overlaps / underlaps portions of the second coil 706, the third coil 708, and the fourth coil 710. The fifth coil 712 is positioned along the bottom of the enclosure 702 below the through-hole 714. All of the coils 704, 708, 710, and 712 overlap each other in areas such that at least a portion of each coil is located above a portion of the other coils, forming an overlapping array.

[0050] The enclosure 702 also defines a curve, as best shown in Figure 11. In other embodiments, the enclosure 702 and the coils therein may define one or more different radii of curvature. A different number of coils may be included in alternative RF-RX arrays, and / or the coils may include different shapes and / or sizes, for example. [Example]

[0051] Various aspects of the subject matter described herein are described in the following numbered examples.

[0052] Example 1 A single-sided magnetic imaging device including a permanent magnet, the permanent magnet having a Z-axis defined to extend perpendicular to the permanent magnet within a field of view and configured to generate a static magnetic field in the Z-axis. The single-sided magnetic imaging device further includes a radio frequency transmit coil configured to generate an electromagnetic field within a target, and a variably tuned radio frequency receive coil configured to detect magnetic flux within the target responsive to the electromagnetic field. The variably tuned radio frequency receive coil is further configured to be tuned to multiple frequencies to match the frequency of the electromagnetic field at a location.

[0053] Example 2 2. The single-sided magnetic imaging apparatus of example 1, wherein adjusting the radio frequency receive coil comprises repositioning the radio frequency transmit coil along the Z axis.

[0054] Example 3 3. The single-sided magnetic imaging device of embodiment 1 or 2, wherein adjusting the radio frequency receiving coil comprises adjusting a current supplied to the radio frequency receiving coil.

[0055] Example 4 4. The single-sided magnetic imaging device of Example 1, 2, or 3, wherein adjusting the radio frequency receive coil comprises rearranging at least one electronic component selected from the group consisting of a varactor, a pin diode, a capacitor, an inductor, a MEMS switch, a solid-state relay, and a mechanical relay.

[0056] Example 5 5. The single-sided magnetic imaging device of example 1, 2, 3, or 4, wherein the radio frequency receive coil comprises a coil printed on a disposable substrate.

[0057] Example 6 6. The single-sided magnetic imaging device of any one of claims 1 to 5, wherein the radio frequency receive coil comprises an array of radio frequency receive coils.

[0058] Example 7 7. The single-sided magnetic imaging apparatus of Example 6, wherein the array of radio frequency receive coils comprises a first coil and a second coil, and the first coil and the second coil are separated.

[0059] Example 8 8. The single-sided magnetic imaging device of example 6 or 7, wherein the array of radio frequency receive coils comprises a first coil and a second coil, the first coil and the second coil being positioned to receive signals from different directions.

[0060] Example 9 9. The single-sided magnetic imaging device of any one of Examples 7 and 8, wherein the first coil and the second coil comprise different shapes.

[0061] Example 10 A single-sided magnetic imaging device as described in Example 6, 7, 8, or 9, wherein the array of radio frequency receiving coils comprises a first coil and a second coil, the first coil and the second coil being aligned longitudinally with the Z axis and offset in the longitudinal direction.

[0062] Example 11 11. The single-sided magnetic imaging device of any one of Examples 7, 8, 9, or 10, wherein the first coil and the second coil partially overlap.

[0063] Example 12 12. The single-sided magnetic imaging device of any one of Examples 7, 8, 9, 10, or 11, wherein the first coil and the second coil are tuned to different frequencies.

[0064] Example 13 13. The single-sided magnetic imaging device of Example 7, 8, 9, 10, 11, or 12, wherein the first coil is tuned to correspond to a first frequency of the electromagnetic field at a location along the Z axis and the second coil is tuned to match a second frequency of the electromagnetic field at a second location along the Z axis.

[0065] Example 14 14. The single-sided magnetic imaging device of Examples 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, and 13, further comprising a housing including a concave outer surface, the permanent magnet being positioned within the housing, and the field of view being outside the housing and offset from the concave outer surface.

[0066] Example 15 A method for calibrating a single-sided magnetic imaging device, the method including generating a static magnetic field in the Z-axis with a permanent magnet, generating an electromagnetic field in a region of interest with a radio frequency transmit coil, and adjusting parameters of a radio frequency receive coil to target an imaging location within the field gradient of the electromagnetic field.

[0067] Example 16 16. The method of example 15, wherein adjusting parameters of the radio frequency receive coil to target an imaging location within the field gradient comprises repositioning the radio frequency transmit coil.

[0068] Example 17 17. The method of example 15 or 16, wherein adjusting parameters of the radio frequency receive coil to target an imaging location within the field gradient comprises adjusting a current supplied to the radio frequency receive coil.

[0069] Example 18 18. The method of example 15, 16, or 17, wherein adjusting parameters of the radio frequency receive coil to target an imaging location within the field gradient comprises rearranging at least one electronic component selected from the group consisting of a varactor, a pin diode, a capacitor, an inductor, a MEMS switch, a solid-state relay, and a mechanical relay.

[0070] Example 19 19. The method of Example 15, 16, 17, or 18, wherein adjusting parameters of the radio frequency receive coil to target an imaging location within the field gradient comprises tuning the radio frequency receive coil to a predetermined frequency based on the target anatomical structure.

[0071] Example 20 20. The method of claim 15, 16, 17, 18, or 19, wherein the magnetic imaging device includes an array of radio frequency receive coils, and the adjusting method further includes tuning coils in the array of radio frequency receive coils to different frequencies.

[0072] While several embodiments have been illustrated and described, it is not the applicant's intention to restrict or limit the scope of the appended claims to such details. Numerous modifications, variations, changes, substitutions, combinations, and equivalents of these embodiments may be implemented and will occur to those skilled in the art without departing from the scope of the present disclosure. Furthermore, the structure of each element associated with the described embodiments can alternatively be described as a means for providing the function performed by the element. Also, where materials are disclosed for particular components, other materials may be used. It should therefore be understood that the foregoing description and the appended claims are intended to cover all such modifications, combinations, and variations as fall within the scope of the disclosed embodiments. The appended claims are intended to cover all such modifications, variations, changes, substitutions, modifications, and equivalents.

[0073] The foregoing detailed description has set forth various aspects of devices and / or processes through the use of block diagrams, flowcharts, and / or examples. To the extent that such block diagrams, flowcharts, and / or examples include one or more functions and / or operations, it will be understood by those skilled in the art that each function and / or operation of such block diagrams, flowcharts, and / or examples, individually and / or collectively, can be implemented by various hardware, software, firmware, or substantially any combination thereof. Those skilled in the art will recognize that some aspects of the embodiments disclosed herein can be equivalently implemented, in whole or in part, as one or more computer programs running on one or more computers (e.g., as one or more programs running on one or more computer systems), as one or more programs running on one or more processors (e.g., as one or more programs running on one or more microprocessors), as firmware, or substantially any combination thereof, on integrated circuits, and that designing circuitry and / or writing code for the software and / or firmware will be well within the skill of those skilled in the art in light of this disclosure. Furthermore, those skilled in the art will understand that the mechanisms of the subject matter described herein can be distributed as one or more program products in a variety of forms, and that the exemplary forms of the subject matter described herein apply regardless of the particular type of signal-bearing medium used for the actual distribution.

[0074] The instructions used to program the logic to implement the various disclosed embodiments can be stored in memory within the system, such as dynamic random access memory (DRAM), cache, flash memory, or other storage. Additionally, the instructions can be distributed over a network or other computer-readable medium. Thus, a machine-readable medium can include, but is not limited to, any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computer), such as a floppy disk, optical disk, compact disk, read-only memory (CD-ROM), and magneto-optical disk, read-only memory (ROM), random access memory (RAM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic or optical card, flash memory, or tangible machine-readable storage used to transmit information via the Internet via electrical, optical, acoustic, or other form of propagated signal (e.g., carrier wave, infrared signal, digital signal, etc.). Thus, a non-transitory computer-readable medium includes any type of tangible machine-readable medium suitable for storing or transmitting electronic instructions or information in a form readable by a machine (e.g., a computer).

[0075] The term "control circuitry" as used in any embodiment herein can refer to, for example, hardwired circuitry, programmable circuitry (e.g., a computer processor including one or more individual instruction processing cores and processing units, processors, microcontrollers, microcontroller units, controllers, digital signal processors (DSPs), programmable logic devices (PLDs), programmable logic arrays (PLAs), or field programmable gate arrays (FPGAs), state machine circuits, firmware that stores instructions executed by the programmable circuitry, and any combination thereof. Control circuitry can be embodied collectively or individually as circuitry that forms part of a larger system, e.g., an integrated circuit (IC), an application specific integrated circuit (ASIC), a system on a chip (SoC), a desktop computer, a laptop computer, a tablet computer, a server, a smartphone, etc. Accordingly, the term "control circuitry" as used herein can refer to, for example, hardwired circuitry, programmable circuitry (e.g., a computer processor including one or more individual instruction processing cores and processing units, processors, microcontrollers, microcontroller units, controllers, digital signal processors (DSPs), programmable logic devices (PLDs), programmable logic arrays (PLAs), or field programmable gate arrays (FPGAs), state machine circuits, firmware that stores instructions executed by the programmable circuitry, and any combination thereof. Control circuitry can be embodied collectively or individually as circuitry that forms part of a larger system, e.g., an integrated circuit (IC), an application specific integrated circuit (ASIC), a system on a chip (SoC), a desktop computer, a laptop computer, a tablet computer, a server, a smartphone, etc. "Control circuitry" includes, but is not limited to, electrical circuitry having at least one discrete electrical circuit, electrical circuitry having at least one integrated circuit, electrical circuitry having at least one application specific integrated circuit, electrical circuitry forming a general purpose computing device configured by a computer program (e.g., a general purpose computer configured by a computer program that at least partially executes the processes and / or devices described herein, or a microprocessor configured by a computer program that at least partially executes the processes and / or devices described herein), electrical circuitry forming a memory device (e.g., in the form of random access memory), and / or electrical circuitry forming a communications device (e.g., a modem, a communications switch, or an optoelectronic device). Those skilled in the art will recognize that the subject matter described herein can be implemented in an analog or digital fashion or some combination thereof.

[0076] The term "logic," as used in any aspect herein, may refer to an app, software, firmware, and / or circuitry configured to perform any of the operations described above. Software may be embodied as a software package, code, instructions, an instruction set, and / or data recorded on a non-transitory computer-readable storage medium. Firmware may be embodied as hard-coded (e.g., non-volatile) code, instructions, or instruction sets, and / or data within a memory device.

[0077] The terms "component," "system," "module," etc., as used in any aspect of this specification may refer to a computer-related entity that is either hardware, a combination of hardware and software, software, or software in execution.

[0078] As used in any aspect of this specification, an "algorithm" refers to a self-consistent sequence of steps leading to a desired result, and the "steps" refer to the manipulation of physical quantities and / or logical states, which may, but need not, take the form of electrical or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated. It is common usage to refer to these signals as bits, values, elements, symbols, characters, terms, numbers, or the like. These and similar terms may be associated with the appropriate physical quantities or are merely convenient labels applied to these quantities and / or states.

[0079] The network may include a packet-switched network. The communication devices may be able to communicate with each other using a selected packet-switched network communication protocol. One exemplary communication protocol may include an Ethernet communication protocol, which may enable communication using the Transmission Control Protocol / Internet Protocol (TCP / IP). The Ethernet protocol may conform to or be compatible with the Ethernet standard published by the Institute of Electrical and Electronics Engineers (IEEE) entitled "IEEE 802.3 Standard," published in December 2008, and / or later versions of this standard. Alternatively or additionally, the communication devices may communicate with each other using the X.25 communication protocol. The X.25 communication protocol may conform to or be compatible with standards published by the Telecommunication Standardization Sector of the International Telecommunication Union (ITU-T). Alternatively or additionally, the communication devices may communicate with each other using a frame relay communication protocol. The frame relay communication protocol may conform to or be compatible with standards published by the Consultative Committee for International Telegraph and Telephone (CCITT) and / or the American National Standards Institute (ANSI). Alternatively or additionally, the transceivers may communicate with each other using an Asynchronous Transfer Mode (ATM) communications protocol. The ATM communications protocol may conform to or be compatible with the ATM standard published by the ATM Forum in August 2001 entitled "ATM-MPRS Network Interworking 2.0," and / or any later versions of this standard. Of course, different and / or later-developed connection-oriented network communications protocols are also contemplated herein.

[0080] Unless otherwise indicated, as will be apparent from the foregoing disclosure, discussions throughout the foregoing disclosure using terms such as "processing," "calculating," "computing," "determining," "displaying," and the like will be understood to refer to the operations and processing of a computer system or similar electronic computing device that manipulates and transforms data represented as physical (electronic) quantities in the computer system's registers and memory into other data similarly represented as physical quantities in the computer system's memory or registers or such other information storage, transmission, or display device.

[0081] As used herein, one or more components may be referred to as being "configured to," "configurable to," "operable to," "adapted to," "capable," "suitable to," etc. Those skilled in the art will recognize that "configured to" can generally encompass active components and / or inactive components and / or standby components, unless the context requires otherwise.

[0082] The terms "proximal" and "distal" are used herein with reference to manipulation of the handle portion or housing of a surgical instrument by a clinician. The term "proximal" refers to the portion closest to the clinician and / or robotic arm, and the term "distal" refers to the portion located away from the clinician and / or robotic arm. Furthermore, it will be understood that for convenience and clarity, spatial terms such as "vertical," "horizontal," "upper," and "lower" may be used herein with respect to the drawings. However, robotic surgical instruments are used in many orientations and positions, and these terms are not intended to be limiting and / or absolute.

[0083] Those skilled in the art will recognize that terms used generally, particularly in the appended claims (e.g., the body of the appended claims), are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "comprising" should be interpreted as "including but not limited to," etc.). Where a particular number of introduced claim recitations are intended, such intention will be expressly recited in the claim, and in the absence of such recitation, it will further be understood by those skilled in the art that no such intention exists. For example, as an aid to understanding, the following appended claims may include the use of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed as meaning that introducing a claim recitation with the indefinite article "a" or "an" limits any particular claim that includes a claim recitation so introduced to claims that contain only one such recitation, even if the same claim also includes the introductory phrase "one or more" or "at least one" and an indefinite article, such as "a" or "an" (e.g., "a" and / or "an" should generally be interpreted to mean "at least one" or "one or more"). The same applies to the use of definite articles used to introduce claim recitations.

[0084] Furthermore, even when a particular number of introduced claim recitations is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., a recitation of "two recitations" alone, without other modifiers, typically means at least two recitations, or more than two recitations). Furthermore, in those instances where a convention similar to "at least one of A, B, and C, etc." is used, such configuration is generally intended in the sense that those skilled in the art would understand the convention (e.g., "a system having at least one of A, B, and C" would include, but be limited to, systems having only A, only B, only C, a combination of A and B, a combination of A and C, a combination of B and C, and / or a combination of A, B, and C, etc.). In those instances where a convention similar to "at least one of A, B, and C, etc." is used, such configuration is generally intended in the sense that one of ordinary skill in the art would understand the convention (e.g., "a system having at least one of A, B, or C" would include, but is not limited to, "a system having A only, B only, C only, A and B together, A and C together, B and C together, and / or A, B, and C together, etc."). Those of ordinary skill in the art will further understand that disjunctive words and / or phrases, whether in the description, claims, or drawings, typically present two or more alternative terms, should be understood to contemplate the possibility of including one of the terms, either of the terms, or both terms, unless the context dictates otherwise. For example, the phrase "A or B" would typically be understood to include the possibilities of "A" or "B" or "A and B."

[0085] With respect to the appended claims, those skilled in the art will understand that the steps described therein may generally be performed in any order. Also, while various process flow diagrams are shown sequentially, it should be understood that various steps may be performed in orders other than those illustrated, or may be performed simultaneously. Examples of such alternative orders include overlapping, interrupted, suspended, reordered, augmented, preliminary, supplemental, simultaneous, reverse, or other variant orderings, unless the context dictates otherwise. Furthermore, terms such as "responsive to," "related to," or other past tense adjectives, etc., are not generally intended to exclude such variants, unless the context dictates otherwise.

[0086] It should be noted that references to "one embodiment," "an embodiment," "an example," "an example," etc., mean that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment. Thus, the appearances of the phrases "in one embodiment," "in an embodiment," "in an example," and "in one example" in various places throughout this specification do not necessarily all refer to the same embodiment. Furthermore, particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0087] Any patent application, patent, non-patent publication, or other disclosure material referred to herein and / or set forth in any Application Data Sheet is incorporated herein by reference to the extent the incorporated material does not contradict this specification. Therefore, and to the extent necessary, the present disclosure as expressly set forth herein supersedes any conflicting material incorporated herein by reference. Although any material, or portion thereof, is purported to be incorporated herein by reference, any material, or portion thereof, that contradicts existing definitions, statements, or other disclosure material set forth herein will be incorporated only to the extent that no contradiction arises between the incorporated material and the existing disclosure material.

[0088] In summary, many advantages resulting from employing the concepts described herein have been described. The foregoing description of one or more embodiments has been presented for purposes of illustration and description. It is not intended to be exhaustive or to be limited to the precise form disclosed. Modifications or variations are possible in light of the above teachings. The one or more embodiments have been selected and described in order to illustrate the principles and practical applications so that those skilled in the art can utilize various embodiments, with various modifications, as suitable for the particular use contemplated. The claims submitted herein are intended to define the entire scope.

Claims

1. A single-sided magnetic imaging device, a permanent magnet, the permanent magnet being configured to generate a static magnetic field in the Z-axis, the Z-axis defined extending perpendicular to the permanent magnet and into a field of view; a radio frequency transmit coil configured to generate an electromagnetic field within the target; a variably tuned radio frequency receiving coil configured to detect magnetic flux within the target responsive to the electromagnetic field; the variably tuned radio frequency receiving coil is further configured to be tuned to a plurality of frequencies to match the frequency of an electromagnetic field at a location; Single-sided magnetic imaging device.

2. 2. The single-sided magnetic imaging device of claim 1, wherein adjusting the radio frequency receive coil comprises repositioning the radio frequency transmit coil along the Z axis.

3. 2. The single-sided magnetic imaging device of claim 1, wherein adjusting the radio frequency receiving coil comprises adjusting a current supplied to the radio frequency receiving coil.

4. 10. The single-sided magnetic imaging device of claim 1, wherein adjusting the radio frequency receiving coil comprises rearranging at least one electronic component selected from the group consisting of varactors, pin diodes, capacitors, inductors, MEMS switches, solid-state relays, and mechanical relays.

5. The single-sided magnetic imaging device of claim 1 , wherein the radio frequency receiving coil comprises a coil printed on a disposable substrate.

6. The single-sided magnetic imaging device of claim 1 , wherein the radio frequency receive coil comprises an array of radio frequency receive coils.

7. 7. The single-sided magnetic imaging device of claim 6, wherein the array of radio frequency receive coils comprises a first coil and a second coil, the first coil and the second coil being separated.

8. 7. The single-sided magnetic imaging device of claim 6, wherein the array of radio frequency receive coils comprises a first coil and a second coil, the first coil and the second coil positioned to receive signals from different directions.

9. The single-sided magnetic imaging device of claim 8 , wherein the first coil and the second coil comprise different shapes.

10. 7. The single-sided magnetic imaging device of claim 6, wherein the array of radio frequency receiving coils comprises a first coil and a second coil, the first coil and the second coil being aligned longitudinally with the Z-axis and offset from each other in the longitudinal direction.

11. The single-sided magnetic imaging device of claim 10 , wherein the first coil and the second coil partially overlap.

12. The single-sided magnetic imaging device of claim 10 , wherein the first coil and the second coil are tuned to different frequencies.

13. 11. The single-sided magnetic imaging device of claim 10, wherein the first coil is tuned to correspond to a first frequency of the electromagnetic field at the location along the Z axis, and the second coil is tuned to match a second frequency of the electromagnetic field at a second location along the Z axis.

14. 10. The single-sided magnetic imaging device of claim 1, further comprising a housing having a concave outer surface, said permanent magnet being positioned within said housing, said field of view being exterior to said housing and offset from said concave outer surface.

15. 1. A method for adjusting a single-sided magnetic imaging device, comprising: generating a static magnetic field in the Z-axis direction by a permanent magnet; generating an electromagnetic field in a region of interest with a radio frequency transmit coil; and adjusting parameters of a radio frequency receive coil to target an imaging location within the field gradient of the electromagnetic field.

16. 16. The method of claim 15, wherein adjusting the parameters of the radio frequency receive coil to target an imaging location within the field gradient comprises repositioning the radio frequency transmit coil.

17. 16. The method of claim 15, wherein adjusting the parameters of the radio frequency receive coil to target an imaging location within the field gradient comprises adjusting a current supplied to the radio frequency receive coil.

18. 16. The method of claim 15, wherein adjusting the parameters of the radio frequency receive coil to target an imaging location within the field gradient comprises rearranging at least one electronic component selected from the group consisting of a varactor, a pin diode, a capacitor, an inductor, a MEMS switch, a solid state relay, and a mechanical relay.

19. 16. The method of claim 15, wherein adjusting the parameters of the radio frequency receive coil to target an imaging location within the field gradient comprises tuning the radio frequency receive coil to a predetermined frequency based on the target anatomy.

20. The method of claim 15 , wherein the magnetic imaging device comprises an array of radio frequency receive coils, and the tuning method further comprises tuning the coils in the array of radio frequency receive coils to different frequencies.

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