Body coil tuning control device having: DC-DC converter with input connected to a DC power supply of an MRI system and output connected to input of an LDO, output of the LDO connected to first connection of a first resistor group; a first opamp with non-inverting input connected to first connection of the first resistor group, inverting input connected to the second connection of the first resistor group, and output connected to gate of a MOSFET array; and a negative feedback circuit connected between the output and the non-inverting input of the first opamp. The MOSFET array has a drain connected to the second connection of the first resistor group and a source connected to the input of the body coil of the MRI system. After the output signal of the first opamp is input to the gate of the MOSFET array, the source outputs a constant preset current.

A magnetic resonance imaging apparatus according to an embodiment includes a static magnetic field magnet, a plurality of radio frequency coils, and processing circuitry. The static magnetic field magnet generates a static magnetic field having a magnetic field strength that changes spatially. The plurality of radio frequency coils receive a nuclear magnetic resonance signal generated from a subject by an influence of a radio frequency pulse transmitted to the subject, the subject being placed in the static magnetic field having a magnetic field strength that changes spatially. The processing circuitry controls each of the plurality of radio frequency coils to receive the nuclear magnetic resonance signal at each of a plurality of frequencies tuned according to at least a distribution of the static magnetic field.

An MRI system RF transmit antenna arrangement 3 including an antenna 5 including a length of coaxial cable 51 with an electrically conductive core 52 and an electrically conductive outer shield 53 through which the core runs, with the core having a feed point 52a arranged for electrical connection to an RF source and at least one break 53a being provided in the electrically conductive outer shield partway along the length of coaxial cable so as to divide the electrically conductive outer shield 53 into at least two axially spaced shield portions such that at least one of the shield portions acts as a radiating element when an RF source is connected to the feed point 52a.

Embodiments described herein relate to detectors and their method of use for sensing electromagnetic fields, electromagnetic signals, biochemical analytes, and/or other conditions in subjects. The device may include an inductively-coupled implantable coil-based transducer that converts electrical, photonic, biochemical signals, and/or other appropriate signals and/or conditions originating in tissues and/or transplanted tissue grafts into changes in a property of the transducer, such as a resonance frequency, that may be detected using an alternating magnetic field that may be provided by a magnetic resonance imaging (MRI) signal and/or other appropriate source. In some embodiments, the detector comprises a FET that changes state upon detection of a subject condition of interest. The change in the FET may change the resonance frequency of an associated LC or RLC circuit. The change in resonance frequency may change the brightness and/or intensity of the detector when detected by an MRI scanner or other appropriate scanner.

A magnetic resonance imaging apparatus includes a T/R switch. The T/R switch includes a double sided microstripline based hybrid couplers with a top side and a bottom side each including two concentric microstripline based hybrid couplers. Each of the two concentric microstripline based hybrid couplers includes an inner microstripline based hybrid coupler and an outer microstripline based hybrid coupler. The inner microstripline based hybrid coupler forms an inner loop of the two concentric microstripline based hybrid couplers and the outer microstripline based hybrid coupler forms an outer loop. In a transmission mode, the inner microstripline based hybrid coupler and the outer microstripline based hybrid coupler at the top side of the dual-tuned T/R switch are activated. In a receiving mode the inner microstripline based hybrid coupler and the outer microstripline based hybrid coupler at the top side and at the bottom side of the dual-tuned T/R switch are activated.

Apparatus for the measurement of ore in mine ore benches or ore stockpiles is disclosed, the apparatus comprising: a mobile platform, defining a platform zone, wherein the mobile platform is positionable on or above a mine ore bench or stockpile; and at least one magnetic resonance (MR) sensor comprised in the mobile platform. The MR sensor includes a main loop and a drive loop located above the main loop. A magnetic resonance sensor control system is provided and configured to control at least one of: the positioning of the at least one MR sensor relative to the platform zone and/or mine ore bench or ore stockpile; the positioning of elements comprised in the MR sensor relative to each other; electromagnetic suppression characteristics of the at least one MR sensor; and/or sensitivity of the at least one MR sensor as a function of distance of the sensor from the mine ore bench or ore stockpile.

The present disclosure provides a magnetic resonance imaging (MRI) radio frequency (RF) coil assembly. The MRI RF coil assembly may include one or more coils and one or more control circuits. Each of the one or more coils may include a first end and a second end. Each of the one or more control circuits may electrically connect the first end and the second end of one of the one or more coil. Each of the one or more control circuits may be configured to adjust an operation of the coil that is electrically connected with the control circuit based on an input control signal. The one or more control circuits may be located at different regions.

A magnetic resonance imaging apparatus includes a T/R switch. The T/R switch includes a double sided microstripline based hybrid couplers with a top side and a bottom side each including two concentric microstripline based hybrid couplers. Each of the two concentric microstripline based hybrid couplers includes an inner microstripline based hybrid coupler and an outer microstripline based hybrid coupler. The inner microstripline based hybrid coupler forms an inner loop of the two concentric microstripline based hybrid couplers and the outer microstripline based hybrid coupler forms an outer loop. In a transmission mode, the inner microstripline based hybrid coupler and the outer microstripline based hybrid coupler at the top side of the dual-tuned T/R switch are activated. In a receiving mode the inner microstripline based hybrid coupler and the outer microstripline based hybrid coupler at the top side and at the bottom side of the dual-tuned T/R switch are activated.

A magnetic resonance (MR) imaging system includes a transmit radio frequency (RF) coil assembly comprising multiple capacitor banks each coupled to at least one diode that is characterized by a high breakdown voltage such that when the transmit RF coil assembly applies at least one slice-selecting RF pulse to a portion of a subject placed in the magnet to select a particular slice for MR imaging, the capacitor banks are selectively adjusted to improve an RF transmission characteristics of the RF coil assembly in transmitting the at least one slice-selecting RF pulse. The MR imaging system may further include a receive radio frequency (RF) coil assembly configured to, in response to at least the slice-selecting RF pulse, receive at least one response radio frequency (RF) pulse emitted from the selected slice of the portion of the subject; a housing; a main magnet; gradient coils; and a control unit.

Signal generation devices including an auto-tuning electronic circuit module for generating tuned output signals are disclosed. The auto-tuning electronic circuit module may include a tunable resonant electronic circuit element for providing a tuned output signal, including a voltage divider element and a tuning array element and control element.