WO2020112891A1 - Systems, methods and apparatus for a passive radiofrequency shield of selective frequency - Google Patents

Systems, methods and apparatus for a passive radiofrequency shield of selective frequency Download PDF

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Publication number
WO2020112891A1
WO2020112891A1 PCT/US2019/063430 US2019063430W WO2020112891A1 WO 2020112891 A1 WO2020112891 A1 WO 2020112891A1 US 2019063430 W US2019063430 W US 2019063430W WO 2020112891 A1 WO2020112891 A1 WO 2020112891A1
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Prior art keywords
frequency
parts
undesired
shield
nuclei
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PCT/US2019/063430
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French (fr)
Inventor
Rock HADLEY
Charles Eric Anderson
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Neotherma Oncology, Inc.
University Of Utah Research Foundation
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Application filed by Neotherma Oncology, Inc., University Of Utah Research Foundation filed Critical Neotherma Oncology, Inc.
Publication of WO2020112891A1 publication Critical patent/WO2020112891A1/en

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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00Arrangements or instruments for measuring magnetic variables
    • G01R33/20Arrangements or instruments for measuring magnetic variables involving magnetic resonance
    • G01R33/28Details of apparatus provided for in groups G01R33/44 - G01R33/64
    • G01R33/42Screening
    • G01R33/422Screening of the radio frequency field
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00Arrangements or instruments for measuring magnetic variables
    • G01R33/20Arrangements or instruments for measuring magnetic variables involving magnetic resonance
    • G01R33/28Details of apparatus provided for in groups G01R33/44 - G01R33/64
    • G01R33/32Excitation or detection systems, e.g. using radio frequency signals
    • G01R33/36Electrical details, e.g. matching or coupling of the coil to the receiver
    • G01R33/3628Tuning/matching of the transmit/receive coil
    • G01R33/3635Multi-frequency operation
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00Arrangements or instruments for measuring magnetic variables
    • G01R33/20Arrangements or instruments for measuring magnetic variables involving magnetic resonance
    • G01R33/44Arrangements or instruments for measuring magnetic variables involving magnetic resonance using nuclear magnetic resonance [NMR]
    • G01R33/48NMR imaging systems
    • G01R33/4808Multimodal MR, e.g. MR combined with positron emission tomography [PET], MR combined with ultrasound or MR combined with computed tomography [CT]
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00Arrangements or instruments for measuring magnetic variables
    • G01R33/20Arrangements or instruments for measuring magnetic variables involving magnetic resonance
    • G01R33/44Arrangements or instruments for measuring magnetic variables involving magnetic resonance using nuclear magnetic resonance [NMR]
    • G01R33/48NMR imaging systems
    • G01R33/4808Multimodal MR, e.g. MR combined with positron emission tomography [PET], MR combined with ultrasound or MR combined with computed tomography [CT]
    • G01R33/4814MR combined with ultrasound

Abstract

The present disclosure provides, inter alia, apparatuses for attenuating undesired frequency and allowing desired frequency, and uses thereof. Systems comprising such apparatuses for inducing regional hyperthermia or ablation in a subject in need thereof in conjunction with a radio-frequency (RF) sensitive device are also provided. Further provided are methods for improving the imaging capacity of multi-nuclear spectroscopy (MNS).

Description

SYSTEMS, METHODS AND APPARATUS FOR A PASSIVE RADIOFREQUENCY

SHIELD OF SELECTIVE FREQUENCY

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims benefit of U.S. Provisional Patent Application Serial No. 62/771 ,436, filed on November 26, 2018, which application is incorporated by reference herein in its entirety.

FIELD OF DISCLOSURE

[0002] The present disclosure relates to inducing regional hyperthermia or ablation via radiofrequency (RF) or ultrasound heating inside of an MRI or otherwise sensitive RF enclosure. This disclosure allows simple method for a heating device at a frequency other than the imaging frequency to be used safely inside an RF sensitive device or enclosure.

BACKGROUND OF THE DISCLOSURE

[0003] With the ability of MRI to measure temperature (Parker et al. 1983), more development is focused on MR guided thermal therapy interventional procedures, such as High-Intensity Focused Ultrasound (HIFU) and Radio Frequency (RF) heating and ablation. These interventions typically use power at frequencies that are very different than the imaging frequency. If there is any significant power used in the MRI scanner for these therapies, the susceptibility and compatibility is not straightforward with MR vendor hardware. In the future, it’s likely that these devices will use other methods of temperature measurement (e.g., Ultrasound Thermometry) that may still be frequency sensitive or need to be located in environments with selective RF permeability (operating rooms).

[0004] There is a need for multi-frequency imaging where two or more different frequencies are applied at the same time while the transmission colils of each frequency do not interact with each other. In some high-power interventional studies an RF shield is used protect the vendor electronics from radiated energy. Flowever, in prior designs shielding power at the interventional frequency attenuates the imaging frequency as well, disallowing use of the system body coil for imaging. Separate transmit and receive hardware would then be required to operate in the thermal therapy environment, inside the shield. The present disclosure relates to systems and methods to address these issues identified above.

SUMMARY OF THE DISCLOSURE

[0005] The present disclosure describes the development of a shield to protect MR vendor hardware from the thermal therapy frequency while being transparent to the imaging frequency for image guidance. Specifically, the body coil could still be used for transmission, even if special RF receiver coils had to be developed for the thermal therapy environment. A design is described and proven to show high attenuation of 13.56MHz energy while being nearly transparent to the 123MHz imaging signal.

[0006] One embodiment of the present disclosure is an apparatus for attenuating undesired frequency and allowing desired frequency. This apparatus comprises: (a) a former for support; (b) a number of parts parallel placed on the outer surface of the former and not overlap or contact with each other; and (c) a number of selective filter circuits that connect each part to its neighbor. [0007] Another embodiment of the present disclosure is a method for attenuating undesired frequency and allowing desired frequency inside a radio frequency (RF) sensitive device. This method comprises: (a) covering a device generating undesired interventional frequency with the apparatus disclosed herein; and (b) placing the covered device inside the RF sensitive device.

[0008] Another embodiment of the present disclosure is a system for inducing regional hyperthermia or ablation in a subject in need thereof in conjunction with a radio-frequency (RF) sensitive device. This system comprises a device generating interventional frequency, wherein the device is covered with an apparatus disclosed herein.

[0009] Yet another embodiment of the present disclosure is a method for improving the imaging capacity of multi-nuclear spectroscopy (MNS). This method comprises: (a) covering a device transmitting and receiving signal of at least one nuclei other than 1FI with the apparatus disclosed herein; and (b) placing the covered device inside an MRI device that transmits and receives 1FI signal.

[0010] A further embodiment of the present disclosure is an apparatus or a system substantially as disclosed in Figs. 1 to 6.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The application file contains at least one photograph executed in color. Copies of this patent application with color photographs will be provided by the Office upon request and payment of the necessary fee.

[0012] The following drawings form part of the present specification and are included to further demonstrate certain aspects of the present disclosure. The disclosure may be better understood by reference to one or more of these drawings in combination with the detailed description of specific embodiments presented herein.

[0013] Fig. 1 shows a prototype of the frequency selective RF shield, including a cardboard former (31 cm diameter, 41 cm length), 32 copper strips (2.5 x 41 cm) spaced with 0.6 cm gaps, and the selective filter circuits that span the gaps, passing 13.56 MFIz and blocking 123 MFIz eddy currents.

[0014] Figs. 2A-2C show series resonance circuits used for passing eddy currents between copper strips in the shield.

[0015] Fig. 2A shows the series resonance circuits for passing eddy currents at 13.56 MHz.

[0016] Fig. 2B shows the series resonance circuits combined with a parallel resonance circuit for blocking eddy currents at 123 MHz. The same 13.56 MHz series resonant circuit as in Fig. 2A with C2 added to create a 123 MHz parallel resonant trap. This trap prevented 123 MHz eddy currents from flowing between copper strips of the shield.

[0017] Fig. 2C shows the S21 profile for each of the circuits in (A, blue curve, S21 ) and (B, red curve, S43). Qucs simulations of the circuits in Fig. 2A and 2B were used to determine standard off-the-shelf components for these circuits.

[0018] Fig. 3 is a schematic of S21 measurements across the shield surface.

[0019] Fig. 4 shows Network analyzer S21 results for the prototype shield using the magnetic test loops across the surface of the shield.

[0020] Fig. 5 shows the SNR maps for a 15 cm diameter phantom using the Body and Flex array coils, without and with the shield. The transmit reference voltage (that is required to achieve a 90 degree flip in the smaple being imaged) for the body coil was 303 and 312 volts, without and with the shield, respectively. Images were acquired using a standard GRE sequence with TR/TE/Flip = 500ms/4ms/90°.

[0021] Fig. 6 shows the simulation results of shielding effectiveness by adjusting the shield configuration.

DETAILED DESCRIPTION OF THE DISCLOSURE

[0022] The present disclosure provides a passive frequency selective RF shield that was designed and constructed to block a single frequency (e.g., 13.56 MHz) from passing through the shield, while being near transparent to other frequency, such as the 123 MHz imaging frequency.

[0023] One embodiment of the present disclosure is an apparatus for attenuating undesired frequency and allowing desired frequency. This apparatus comprising: (a) a former for support; (b) a number of parts placed on the outer surface of the former and not overlap or contact with each other; and (c) a number of selective filter circuits that connect each part to its neighbor.

[0024] As used herein, “attenuating” or“attenuation” means to weaken or reduce a signal (e.g., a radio-frequency) in force, intensity, power, or effect. In some embodiments, the apparatus is capable of attenuating the undesired frequency by about 20 dB or more.

[0025] In some embodiments, the apparatus further comprises a number of parts placed on the inner surface of the former and not overlap or contact with each other. In some embodiments, the part is in the form of a strip, a patch, or a plate with regular or irregular shape. In some embodiments, the part is a strip. In some embodiments, the parts are arranged parallel to each other. In some embodiments, the parts are offset patches.

[0026] In some embodiments, the former is of sufficient dimension to accommodate a device that generates electromagnetic radiation (EMR). As used herein, an“electromagnetic radiation”,“EM radiation” or“EMR” refers to the waves (or their quanta, photons) of the electromagnetic field, propagating (radiating) through space, carrying electromagnetic radiant energy. Non-limiting examples of an electromagnetic radiation include radio waves, microwaves, infrared, (visible) light, ultraviolet, X-rays, and gamma rays. In some embodiments, the device that generates EMR is a radio frequency (RF) device.

[0027] In some embodiments, the former is made of a non-conductive material such as, for example, cardboard, glass, textile, rubber, wood, plastic, or polymer.

[0028] In some embodiments, the parts are made of a conductive material. As used herein, a“conductive material” refers to a type of material that allows the flow of an electrical current in one or more directions. Non-limiting examples of a conductive material include metal, e.g., gold, silver, copper, iron, aluminum, cadmium, chromium, steel, galvanized steel, nickel, brasses, monel, inconel, titanium, platinum, other alloys thereof, and non-metal such as, e.g., graphite. In some embodiments, the parts are made of copper.

[0029] In some embodiments, the distance between each part is adjustable. In some embodiments, the distance between each part is greater than 0 and less than

10 mm. [0030] In some embodiments, the effectiveness of the apparatus can be tuned by modifying at least one of the following factors: the number of selective filter circuits, the arrangement of the selective filter circuits, the number of the parts, the distance between each part, the width of the parts, the length of the parts, the thickness of the parts, the material of the parts, and combinations thereof.

[0031] In some embodiments, the apparatus can be tuned to attenuate a frequency in the range of 0.5 MHz to 2 GHz.

[0032] In some embodiments, the undesired frequency is lower than the desired frequency. In some embodiments, the undesired frequency is a signal of at least one nuclei other than 1H and the desired frequency is a signal of 1H. In some embodiments, the at least one nuclei other than 1H has a lower gyromagnetic ratio (y) than 1H. In some embodiments, the at least one nuclei other than 1H is selected from the group consisting of 3He, 13C, 19F, 23Na, 31P, and 129Xe. As used herein, “gyromagnetic ratio” or“magnetogyric ratio” of a particle or system is the ratio of its magnetic moment to its angular momentum, and it is often denoted by the symbol y, gamma.

[0033] Another embodiment of the present disclosure is a method for attenuating undesired frequency and allowing desired frequency inside a radio frequency (RF) sensitive device. This method comprises: (a) covering a device generating undesired interventional frequency with the apparatus disclosed herein; and (b) placing the covered device inside the RF sensitive device.

[0034] As used herein,“radio-frequency” or“RF” refers to an oscillation rate of an alternating electric current or voltage or of a magnetic, electric or electromagnetic field or mechanical system in the frequency range from around one million times per second (1 MHz) to around three hundred billion times per second (300 GHz).

[0035] In some embodiments, the undesired frequency is a heating frequency. In some embodiments, the undesired frequency is about 13 MHz.

[0036] In some embodiments, the permissive frequency is an MRI imaging frequency. In some embodiments, the permissive frequency is about 123 MHz.

[0037] Another embodiment of the present disclosure is a system for inducing regional hyperthermia or ablation in a subject in need thereof in conjunction with a radio-frequency (RF) sensitive device. This system comprises a device generating interventional frequency, wherein the device is covered with an apparatus disclosed herein.

[0038] In some embodiments of the present disclosure, the RF sensitive device is an MRI device.

[0039] Yet another embodiment of the present disclosure is a method for improving the imaging capacity of multi-nuclear spectroscopy (MNS). This method comprises: (a) covering a device transmitting and receiving signal of at least one nuclei other than 1H with the apparatus disclosed herein; and (b) placing the covered device inside an MRI device that transmits and receives 1H signal.

[0040] In some embodiments, the at least one nuclei other than 1H has a lower gyromagnetic ratio (y) than 1H. In some embodiments, the at least one nuclei other than 1 H is selected from the group consisting of 3He, 13C, 19F, 23Na, 31P, and 129Xe.

[0041] A further embodiment of the present disclosure is an apparatus or a system substantially as disclosed in Figs. 1 to 6. [0042] The following examples are provided to further illustrate the methods of the present disclosure. These examples are illustrative only and are not intended to limit the scope of the disclosure in any way.

EXAMPLES

Example 1

The RF shield blocks the thermal therapy frequency, while passing the imaging frequency

[0043] The frequency-selective shield was implemented on a cardboard cylinder with a 31 cm diameter and 41 cm length. 32 strips of copper tape, 2.54cm width and 41 cm in length, were positioned around the cylinder with gaps of approximately 0.6cm (Fig. 1 ).

[0044] The shield was first constructed using the series resonant circuit (Fig. 2A) to span the gaps between copper strips. This circuit allowed the 13.56 MFIz eddy currents to flow freely between copper strips as they would in a solid copper shield, limited only by the number and spacing of the filter circuits. Flowever, S21 measurements across the surface of the shield resulted in more attenuation of the 123MFIz imaging frequency than was desired. The filter circuits were then modified (Fig. 2B) to include a parallel resonant trap to block 123MFIz eddy currents from flowing through the filter circuits, therefore significantly reducing 123 MFIz eddy currents in the shield.

[0045] To minimize the number of components and associated costs, Qucs simulations (Fig. 2C) were performed to determine components with standard off- the-shelf values for the filter circuits (http://qucs.sourceforqe.net/3). For the circuits in Figs. 2A-2C, the components C1 = 2200pF and L1 = 63.6nFI formed the 13.56 series resonance. The addition of C2 = 27pF formed the parallel resonant blocking circuit. For this modified circuit, the inductor L1 was adjusted to 63nFI for best attenuation at 123MFIz. Capacitors were non-magnetic (Knowles Syfer), and the inductors were variable (Coilcraft).

[0046] To determine how many filter circuits would be required along each gap; four test conditions were established consisting of 1 , 3, 5, and 7 filter circuits soldered between strips at evenly-spaced intervals along each gap of the shield. Shielding effectiveness was assessed for each test condition with S21 measurements between two large test loops (Hoult, 2000) that were approximately 16.5cm in diameter and positioned on opposite sides of the shield surface (Fig. 3).

[0047] Finally, using the modified filter circuit (Fig. 2B), imaging experiments were performed using the Body coil only and with the Body/Siemens 4-chFlex array to asses phantom SNR with and without the shield in place. The phantom was a 15cm diameter plastic bottle filled with CUSO4 and NaCI solution. SNR maps were generated for each imaging study using the Kellmen method (Kellman and McVeigh, 2005).

[0048] The prototype shield for this work is shown in Fig. 1 with 7 filter circuits across each gap. S21 measurements of the filter circuits were very similar to the Qucs predictions (Fig. 2C).

[0049] The shield S21 measurements (Table 1 ) indicate that 13.56 MFIz shielding was essentially equal for both filter circuits, but the addition of C2 improved the 123MFIz transparency of the shield significantly. Table 1: Frequency selective Shield S21 Measurements

Figure imgf000013_0001

[0050] Table 1 shows the average S21 measurements for 2 approximately 16.5 cm diameter test loops placed on opposite sides of the shield surface. One loop was inside the shield and one loop was outside the shield. As expected, the shield effectiveness improved as more shunt circuits were added to span the gap between copper strips. The 123 MHz blocking circuit significantly improved the transparency of the shield at the imaging frequency.

[0051] Shield S21 measurements from the Vector Network Analyzer are shown in Fig. 4. With 7 filtrer circuits across each gap, this prototype shield provides ~18 dB attenuation at 13.56 MHz (marker 1 ) with minimal attenuation at 123 MHz (marker 2).

[0052] In the imaging study results (Fig. 5), little difference can be observed in the body coil images and only subtle differences in the Flex coil images can be seen. It appears that the shield does attenuate the transmit signal slightly as the transmit reference voltage changed from 304 volts without the shield to 313 volts with the phantom inside the shield.

[0053] The shield developed in the present disclosure provided the desired effect of shielding the thermal therapy frequency of 13.56MHz by 17-20 dB, while passing the imaging frequency of 123MHz with less than 0.5 dB attenuation. [0054] Being a feasibility study, many of the shield parameters have not been optimized (i.e. , copper strip length, width, and spacing, and filter circuit effectiveness and placement). Certain works that optimize the performance of this shielding concept are described in the following example.

[0055] The present disclosure demonstrates that an RF shield can be constructed to provide significant shielding at a particular frequency of concern to prevent coupling into vendor system hardware, while being nearly transparent to the MR imaging frequency for MR guided therapy purposes.

Example 2

Tuned Shiled Simulations

[0056] A series of simulations were performed to provide a guidance to optimize the configuration of the shield (including, e.g., strip widths and gap sizes). These items can also be used to specify the strength of the shielding for each particular application.

[0057] In this work, we designed the properties of the shielding desired for the application in silico using Finite Difference Time Domain simulation of the electromagnetic response using commercial software. A 300 mm sheet of shielding of various designs as specified was tested. Two 100 mm diameter loops spaced by 50mm on each side of the shield were used to check for the response of the shield by inspecting the power coupling (S21 ) between the loops. Boundary conditions and convergence were checked using built-in tools. A consistency check was utilized for each simulation by running with and without the shield geometry, and by running each shield geometry with and without the filter circuits. A selection of data demonstrated the response of the shield to a change in the strip spacing and strip width over a consistent area.

[0058] As summarized in Fig. 6, increasing strip width had a nearly linear response to increasing the relative shield effectiveness (effectiveness over open shielding alone). Increasing the gap size of the shielding had little effective of the relative shielding effectiveness of the filter design, but did show the underlying response of overall shielding seen in the shield geometry alone. In this way, the underlying shielding should be first designed to show acceptable passage of the desired frequency first, with the number and placement filter circuits added as needed to achieve the specific shielding needs of the stop-band as specified by the application needs.

DOCUMENTS CITED

1. Parker DL, Smith V, Sheldon P, Crooks LE, Fussell L. Temperature distribution measurements in two-dimensional NMR imaging. Med Phys 1983; 10(3):321 -5.2.

2. http://qucs.sourceforge. net/3.

3. Hoult Dl. The Principle of Reciprocity in Signal Srength Calculations: A Mathematical Guide. Concepts Magn Reson A 2000; 12: 173-187.4.

4. Kellman P, McVeigh ER. Image Reconstruction in SNR Units: A Geneal Method for SNR Measurement. Magn Reson Med. 2005 December; 54(6): 1439-1447. [0059] All documents cited in this application are hereby incorporated by reference as if recited in full herein.

[0060] Although illustrative embodiments of the present disclosure have been described herein, it should be understood that the disclosure is not limited to those described, and that various other changes or modifications may be made by one skilled in the art without departing from the scope or spirit of the disclosure.

Claims

WHAT IS CLAIMED IS:
1. An apparatus for attenuating undesired frequency and allowing desired frequency, comprising:
(a) a former for support;
(b) a number of parts placed on the outer surface of the former and not overlap or contact with each other; and
(c) a number of selective filter circuits that connect each part to its neighbor.
2. The apparatus of claim 1 , further comprising a number of parts placed on the inner surface of the former and not overlap or contact with each other.
3. The apparatus of claim 1 , wherein the part is in the form of a strip, a patch, or a plate with regular or irregular shape.
4. The apparatus of claim 3, wherein the part is a strip.
5. The apparatus of claim 1 , wherein the parts are arranged parallel to each other.
6. The apparatus of claim 1 , wherein the parts are offset patches.
7. The apparatus of claim 1 , wherein the former is of sufficient dimension to accommodate a device that generates electromagnetic radiation (EMR).
8. The apparatus of claim 7, wherein the device that generates EMR is a radio frequency (RF) device.
9. The apparatus of claim 1 , wherein the former is made of a non-conductive material.
10. The apparatus of claim 1 , wherein the parts are made of a conductive material.
11. The apparatus of claim 9, wherein the conductive material is selected from the group consisting of gold, silver, copper, iron, aluminum, cadmium, chromium, steel, galvanized steel, nickel, brasses, monel, inconel, titanium, platinum, other alloys thereof, and graphite.
12. The apparatus of claim 1 , wherein the parts are made of copper.
13. The apparatus of claim 1 , wherein the distance between each part is adjustable.
14. The apparatus of claim 1 , wherein the distance between each part is greater than 0 and less than 10 mm.
15. The apparatus of claim 1 , wherein the effectiveness of the apparatus can be tuned by modifying at least one of the following factors: the number of selective filter circuits, the arrangement of the selective filter circuits, the number of the parts, the distance between each part, the width of the parts, the length of the parts, the thickness of the parts, the material of the parts, and combinations thereof.
16. The apparatus of claim 1 , wherein the apparatus can be tuned to attenuate a frequency in the range of 0.5 MHz to 2 GHz.
17. The apparatus of claim 1 , wherein the apparatus is capable of attenuating the undesired frequency by about 20 dB or more.
18. The apparatus of claim 1 , wherein the undesired frequency is lower than the desired frequency.
19. The apparatus of claim 1 , wherein the undesired frequency is a signal of at least one nuclei other than 1H and the desired frequency is a signal of 1H.
20. The apparatus of claim 19, wherein the at least one nuclei other than 1H has a lower gyromagnetic ratio (y) than 1H.
21 . The apparatus of claim 19, wherein the at least one nuclei other than 1H is selected from the group consisting of 3He, 13C, 19F, 23Na, 31 P, and 129Xe.
22. A method for attenuating undesired frequency and allowing desired frequency inside a radio-frequency (RF) sensitive device, comprising:
(a) covering a device generating undesired interventional frequency with the apparatus according to any one of claim 1 to 21 ; and
(b) placing the covered device inside the RF sensitive device.
23. The method of claim 22, wherein the RF sensitive device is an MRI device.
24. The method of claim 22, wherein the undesired frequency is a heating frequency.
25. The method of claim 22, wherein the undesired frequency is about 13 MFIz.
26. The method of claim 22, wherein the permissive frequency is an MRI imaging frequency.
27. The method of claim 22, wherein the permissive frequency is about 123 MFIz.
28. A system for inducing regional hyperthermia or ablation in a subject in need thereof in conjunction with a radio-frequency (RF) sensitive device, comprising a device generating interventional frequency,
wherein the device is covered with an apparatus according to any one of claim 1 to 21.
29. The system of claim 28, wherein the RF sensitive device is an MRI device.
30. An apparatus or a system substantially as disclosed in Figures 1 to 6.
31. A method for improving the imaging capacity of multi-nuclear spectroscopy (MNS), comprising:
(a) covering a device transmitting and receiving signal of at least one nuclei other than 1FI with the apparatus according to any one of claim 1 to 21 ; and (b) placing the covered device inside an MRI device that transmits and receives 1H signal.
32. The method of claim 31 , wherein the at least one nuclei other than 1H has a lower gyromagnetic ratio (y) than 1H.
33. The method of claim 31 , wherein the at least one nuclei other than 1H is selected from the group consisting of 3He, 13C, 19F, 23Na, 31 P, and 129Xe.
PCT/US2019/063430 2018-11-26 2019-11-26 Systems, methods and apparatus for a passive radiofrequency shield of selective frequency WO2020112891A1 (en)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5396173A (en) * 1992-04-09 1995-03-07 Kabushiki Kaisha Toshiba RF magnetic shield for MRI
US7501826B2 (en) * 2006-08-30 2009-03-10 Siemens Aktiengesellschaft Dividing wall separating the RF antenna from the patient chamber in an MR scanner
US8035384B2 (en) * 2008-10-23 2011-10-11 General Electric Company Hybrid birdcage-TEM radio frequency (RF) coil for multinuclear MRI/MRS
US20130131496A1 (en) * 2009-06-16 2013-05-23 MRI Interventions, Inc. Mri-guided catheters
US8522977B1 (en) * 2012-09-11 2013-09-03 Google Inc. Method and system for protective radio frequency shielding packaging
US20180015294A1 (en) * 2016-07-18 2018-01-18 Neotherma Oncology, Inc. Systems and methods for targeted deep hyperthermia by time-shared rf inductive applicators

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5396173A (en) * 1992-04-09 1995-03-07 Kabushiki Kaisha Toshiba RF magnetic shield for MRI
US7501826B2 (en) * 2006-08-30 2009-03-10 Siemens Aktiengesellschaft Dividing wall separating the RF antenna from the patient chamber in an MR scanner
US8035384B2 (en) * 2008-10-23 2011-10-11 General Electric Company Hybrid birdcage-TEM radio frequency (RF) coil for multinuclear MRI/MRS
US20130131496A1 (en) * 2009-06-16 2013-05-23 MRI Interventions, Inc. Mri-guided catheters
US8522977B1 (en) * 2012-09-11 2013-09-03 Google Inc. Method and system for protective radio frequency shielding packaging
US20180015294A1 (en) * 2016-07-18 2018-01-18 Neotherma Oncology, Inc. Systems and methods for targeted deep hyperthermia by time-shared rf inductive applicators

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