Abstract: Nuclear magnetic resonance (MR) imaging can include use of an electrical transceiver coil system comprising an array of segmented loops. The array can be arranged about a portion of an imaging subject and arranged to provide surgical access to a region of the imaging subject from at least one direction. The segmented loops can establish a volumetric radio frequency (RF) excitation field across a volume-of-interest associated with the imaging subject in response to the segmented loops receiving specified transmit phases providing a non-90-degree relative phase between segmented coil loops at adjacent ones of the segmented loops. All or at least some of the segmented loops can provide outputs indicative of an RF signal from the imaging subject, the RF signal elicited in response to RF excitation. The transceiver coil system can facilitate pre-operative, intra-operative, or post-operative MR imaging, such as facilitating access for a surgical procedure.

Abstract: An phased array RF coil used for MR imaging is designed so that it remains in place in the field of view of an X-Ray imaging system and comprises a support board on which copper or aluminum conductive traces are carried. The attenuation of the X-Rays caused by the traces is visible in the radiation image but this is compensated by arranging the non-conductive material of the support board such that the attenuation is substantially constant. The phased array includes individual coil loops which are overlapped with the traces being of half thickness at crossing locations of the traces and with one of the loops on one side and the other loop on the second side of the substrate sheet.

Abstract: In a method for imaging a body part of a patient particularly in relation to DBS where conductive elements can reduce a safe SAR level, the power in the RF pulses being delivered to the RF transmit coil is measured in real time by a unit associated with the FR transmit coil and is used to stop the supply of RF pulses to the RF coil in the event that the power exceeds a predetermined safe limit. As signal can also be transmitted to the MR control unit to shut off the imaging sequence.

Abstract: A receive coil for MRI includes a stacked pair of coil elements to communicate the respective MR signals therein to the signal processing system in separate channels. This greatly increases image SNR and penetration depth and in parallel imaging. The coils are arranged in a stacked relationship so as to be at least partly and preferably wholly overlapped and lying in the same or closely adjacent planes. The coils include tuning capacitors to a common resonant frequency. The coils are connected by a conductor arranged such that the signals of the first and second coils are decoupled. The conductor can form a common portion of the coils including a capacitance of in the common portion arranged. The coils can be connected by two conductors one of which is a short and the other contains a capacitor. In both cases the connection conductors provide the decoupling.

Abstract: The receive coil arrangement includes an inner coil adjacent the part to be imaged so as to maximize the received MR signal and an outer coil, which may be the built in body coil of the magnet, connected by cable to the signal processing system. Both the coils are individually tuned to the common resonant frequency and the receive coil include an arrangement to halt current flow therein during the transmit stage. The first coil has no cable and is arranged to communicate the MR signal therein to the signal processing system through the outer coil by inducing the MR signal onto the outer coil. Despite inherent losses by interfering with the tuning of the loops and in the inductive coupling this magnifies the MR signal and makes the first coil wireless. Arrangements are provided for generating from the output of the second coil separate signals for separate channels of the signal processing unit.

Abstract: The receive coil arrangement includes an inner local volume coil adjacent the part to be imaged so as to maximize the received MR signal and an outer coil, which may be the built in body coil of the magnet, connected by cable to the signal processing system. Both the coils are individually tuned to the common resonant frequency and the local volume coil include an arrangement to halt current flow therein during the transmit stage. The local volume coil has no cable and is arranged to communicate the MR signal therein to the signal processing system through the outer coil by inductive coupling to the outer coil. Despite inherent losses by interfering with the tuning of the loops and in the inductive coupling this magnifies the MR signal and makes the local volume coil wireless.

Abstract: A receive coil for MRI includes a stacked pair of coil elements to communicate the respective MR signals therein to the signal processing system in separate channels. This greatly increases image SNR and penetration depth and in parallel imaging. The coils are arranged in a stacked relationship so as to be at least partly and preferably wholly overlapped and lying in the same or closely adjacent planes. The coils include tuning capacitors to a common resonant frequency. The coils are connected by a conductor arranged such that the signals of the first and second coils are decoupled. The conductor can form a common portion of the coils including a capacitance of in the common portion arranged. The coils can be connected by two conductors one of which is a short and the other contains a capacitor. In both cases the connection conductors provide the decoupling.

Abstract: An phased array RF coil used for MR imaging is designed so that it remains in place in the field of view of an X-Ray imaging system and comprises a support board on which copper or aluminum conductive traces are carried. The attenuation of the X-Rays caused by the traces is visible in the radiation image but this is compensated by arranging the non-conductive material of the support board such that the attenuation is substantially constant. The phased array includes individual coil loops which are overlapped with the traces being of half thickness at crossing locations of the traces and with one of the loops on one side and the other loop on the second side of the substrate sheet.

Abstract: The receive coil arrangement includes an inner coil adjacent the part to be imaged so as to maximize the received MR signal and an outer coil, which may be the built in body coil of the magnet, connected by cable to the signal processing system. Both the coils are individually tuned to the common resonant frequency and the receive coil include an arrangement to halt current flow therein during the transmit stage. The first coil has no cable and is arranged to communicate the MR signal therein to the signal processing system through the outer coil by inducing the MR signal onto the outer coil. Despite inherent losses by interfering with the tuning of the loops and in the inductive coupling this magnifies the MR signal and makes the first coil wireless. Arrangements are provided for generating from the output of the second coil separate signals for separate channels of the signal processing unit.

Abstract: The receive coil arrangement includes an inner local volume coil adjacent the part to be imaged so as to maximize the received MR signal and an outer coil, which may be the built in body coil of the magnet, connected by cable to the signal processing system. Both the coils are individually tuned to the common resonant frequency and the local volume coil include an arrangement to halt current flow therein during the transmit stage. The local volume coil has no cable and is arranged to communicate the MR signal therein to the signal processing system through the outer coil by inductive coupling to the outer coil. Despite inherent losses by interfering with the tuning of the loops and in the inductive coupling this magnifies the MR signal and makes the local volume coil wireless.

Abstract: Radiation therapy of a lesion in a part of a patient is carried out by maintaining the patient on a patient support table in fixed position using an immobilization device while the table is rotated between a magnetic resonance imaging system, a CT imaging system for generating a 360 degree scanned image of the patient at the location of the lesion and the radiation therapy system for generating a beam of radiation for treatment of the lesion and for scanning the beam 360 degrees around the lesion. The MR image locates the lesion and the CT system is used to calculate the treatment. Registration between the MR image, the CT image and the radiation treatment is provided by the fixed position of the part of the patient on the table which is held fixed using an immobilization system suitable for the part concerned which may include a molded head mask where the head is involved.

Abstract: An MRI phase RF coil array includes a plurality of separate RF coil elements where each coil element has a pre-amplifier circuit with a conditioning circuit in advance of the transistor including an inductor and capacitors connected across the input of preamplifier. Each of the coil elements has a preamplifier decoupling parallel resonant circuit for generating a tuned high impedance across the ends of the coil so as to inhibit coupling in the coil from signals in adjacent and non-adjacent coils of the array. The decoupling circuit comprises a fixed first capacitor across the ends, a second variable capacitor in one of the leads, a further capacitor in the conditioning circuit, all of which define a capacitance which co-operates with the inductance defined by the inductor of the conditioning circuit of preamplifier to form the parallel resonant circuit to generate the high impedance.

Abstract: An MRI phase RF coil array includes a plurality of separate RF coil elements where each coil element has a pre-amplifier circuit with a conditioning circuit in advance of the transistor including an inductor and capacitors connected across the input of preamplifier. Each of the coil elements has a preamplifier decoupling parallel resonant circuit for generating a tuned high impedance across the ends of the coil so as to inhibit coupling in the coil from signals in adjacent and non-adjacent coils of the array. The decoupling circuit comprises a fixed first capacitor across the ends, a second variable capacitor in one of the leads, a further capacitor in the conditioning circuit, all of which define a capacitance which co-operates with the inductance defined by the inductor of the conditioning circuit of preamplifier to form the parallel resonant circuit to generate the high impedance.

Abstract: Radiation therapy of a lesion in a part of a patient is carried out by maintaining the patient on a patient support table in fixed position using an immobilization device while the table is rotated between a magnetic resonance imaging system, a CT imaging system for generating a 360 degree scanned image of the patient at the location of the lesion and the radiation therapy system for generating a beam of radiation for treatment of the lesion and for scanning the beam 360 degrees around the lesion. The MR image locates the lesion and the CT system is used to calculate the treatment. Registration between the MR image, the CT image and the radiation treatment is provided by the fixed position of the part of the patient on the table which is held fixed using an immobilization system suitable for the part concerned which may include a molded head mask where the head is involved.

Abstract: Signals in an RF field, such as that of an MRI system, are communicated through an inner conductor having an outer shield with a dielectric material therebetween and an outer cable jacket. Current in the shield caused by the RF field from the transmit body coil is reduced by providing a second dielectric material around the shield conductor and a plurality of segmented shield conductor portions formed of non-magnetic braid or wrapped non-magnetic foil tape outside the second dielectric material and inside the jacket at spaced positions along the cable, with the portions being electrically separated from each other and from the shield so that the segmented shield conductor portions act to shield the outer shield conductor to reduce the generation of current thereon while the electrical separation of the segmented shield conductor portions each from the others prevents the generation of a current along the portions.

Abstract: Signals in an RF field, such as that of an MRI system, are communicated through an inner conductor having an outer shield with a dielectric material therebetween and an outer cable jacket. Current in the shield caused by the RF field from the transmit body coil is reduced by providing a second dielectric material around the shield conductor and a plurality of segmented shield conductor portions formed of non-magnetic braid or wrapped non-magnetic foil tape outside the second dielectric material and inside the jacket at spaced positions along the cable, with the portions being electrically separated from each other and from the shield so that the segmented shield conductor portions act to shield the outer shield conductor to reduce the generation of current thereon while the electrical separation of the segmented shield conductor portions each from the others prevents the generation of a current along the portions.