G01R33/4215

MR system with partial shielding cabin and method for operation

A magnetic resonance tomography (MRT) unit includes a field magnet, a transmitter, and a transmitting antenna. The MRT unit also has a transmission interference suppression facility with a transmission interference suppression controller, a plurality of sensors, and a transmission interference suppression antenna. The transmission interference suppression facility is configured to pick up, with the sensors, an excitation signal of the transmitter, determine, with the transmission interference suppression controller, a transmission interference suppression signal as a function of the excitation signal of the transmitter, and emit the signal via the transmission interference suppression antenna, so that at a predetermined location outside of the MRT unit, an electromagnetic alternating field of an excitation signal emitted by the transmitter via the transmitting antenna is attenuated. The sensors are arranged in a near field of the transmitting antenna, and the predetermined location of the attenuation is in a far field of the transmitting antenna.

Thermal Bus Structure for a Magnetic Resonance Imaging Device
20240004008 · 2024-01-04 · ·

A magnetic resonance imaging device including a main magnet, a gradient system with at least one gradient coil, a cryocooler, a thermal bus structure, and an electromagnetic shield arranged between the gradient system and the main magnet. The electromagnetic shield includes spaced shield elements. The electromagnetic shield is configured to provide an electromagnetic shielding of the main magnet from a magnetic field generated by the at least one gradient coil. The thermal bus structure includes thermal bus elements configured to provide a thermal connection between the plurality of spaced shield elements and a cold head of the cryocooler. At least two thermal bus elements of thermal bus elements include different heat transfer properties to provide individualized temperature control of the spaced shield elements.

Magnetic Resonance Scanner with Passively Shielded Gradient Coil
20240004013 · 2024-01-04 · ·

A magnetic resonance MR scanner utilizing a passive magnetic shielding technique. The scanner includes a gradient coil inductively coupled to a managed eddy current structure which establishes passive magnetic shielding for the gradient coil due to the inductive coupling.

Thermal Bus Structure for a Magnetic Resonance Imaging Device

The disclosure relates to a magnetic resonance imaging device comprising a main magnet, a gradient system including at least one gradient coil, a thermal bus structure, a shield structure arranged between the gradient system and the main magnet and a cryocooler including a cold head, wherein the shield structure is configured to reduce a transport of heat energy to the main magnet and wherein the main magnet comprises a magnet spacer configured for spacing individual coils of the main magnet, wherein the thermal bus structure comprises at least one thermal bus element extending through the magnet spacer for providing a thermal connection between the cold head of the cryocooler and the shield structure.

Gradient Coil Unit Free of Active Screening
20240004011 · 2024-01-04 · ·

A gradient coil unit is described that is designed as a hollow cylinder surrounding a patient receiving region in the longitudinal direction and is subdivisible into four quadrants, comprising a primary coil including a conductor structure that includes a geometric arrangement of an electrical conductor with a conductor cross-section arranged within a quadrant of the four quadrants. The quadrant comprises at least one neutral region, which is defined in the longitudinal direction between a first longitudinal position and a second longitudinal position, and characterized in that the current density averaged over the neutral region is less than 25% of the maximum current density averaged over the conductor cross-section within the neutral region. The gradient coil unit is free of a secondary coil and/or free of an active screening.

Particle therapy apparatus comprising an MRI
10874878 · 2020-12-29 · ·

The present disclosure relates to a particle therapy apparatus for irradiating a target with a charged particle beam. In one implementation, the apparatus includes an isocentric gantry rotatable about an axis and configured to direct a particle beam towards an isocenter of gantry and according to a final beam direction, a magnetic resonance imaging system configured to generate a main magnetic field parallel to the final beam direction, and a passive magnetic shield surrounding the magnetic resonance imaging system, the passive magnetic shield and the magnetic resonance imaging system being synchronously rotatable with the gantry about the axis.

Vibration reduction for a magnetic resonance imaging apparatus

According to one embodiment, a magnetic resonance imaging apparatus includes: a cylindrical magnetic pole for generating a static magnetic field in an imaging region; a cylindrical gradient magnetic field coil arranged on a radially inner side of the magnetic pole, coaxially with the magnetic pole to generate a dynamic magnetic field having a linear magnetic field strength in the imaging region; a cylindrical high frequency coil arranged on a radially inner side of the gradient magnetic field coil, coaxially with the magnetic pole and the gradient magnetic field coil to generate a high frequency magnetic field in the imaging region; and a computer system for processing signals to obtain images. The magnetic resonance imaging apparatus further includes at least two loop-shaped additional coils arranged on the radially outer side of the gradient magnetic field coil and having different electric current circulating direction.

MAGNETIC RESONANCE IMAGING DEVICE AND SUPERCONDUCTING MAGNET

Provided are a magnetic resonance imaging device and a superconducting magnet capable of preventing generation of eddy currents accompanying vibration of a radiation shield and of reducing image quality deterioration. The superconducting magnet for a magnetic resonance imaging device includes a substantially cylindrical vacuum vessel, a substantially cylindrical radiation shield that is provided inside the vacuum vessel, and a superconducting coil that is provided inside the radiation shield. The radiation shield has an inner cylinder located radially inward of the superconducting coil. The inner cylinder of the radiation shield is provided with an annular rib formed in a circumferential direction about the central axis of the inner cylinder.

Local active gradient shielding

Some implementations provide a system that includes: a main magnet including a bore and configured to generate a substantially uniform magnetic field in the bore; one or more gradient coils configured to perturb the substantially uniform magnetic field in the bore, wherein perturbing the substantially uniform magnetic field results in a first varying magnetic field outside of the bore; and one or more shielding units located outside of the bore and configured to generate a second varying magnetic field configured to attenuate the first varying magnetic field outside of the bore.

COIL SYSTEM WITH DIFFERENT CURRENTS DRIVEN THROUGH THE SHIELD AND PRIMARY COILS
20200355768 · 2020-11-12 ·

The present disclosure provides a system and method for generating a magnetic field within a magnetic resonance imaging (MRI) apparatus having an imaging region. The coil system comprises a primary coil for generating the magnetic field in the MRI apparatus and is positioned at a first distance from the imaging region. The primary coil is also configured to be driven at a first current. The coil system also includes a shield coil positioned at a second distance, that is larger than the first distance, from the imaging region. The shield coil is configured to be driven at a second current that is different in magnitude than the first current. The shield coil is thus adapted to reduce the magnetic field outside of the shield coil when the primary coil is driven at the first current and the shield coil is driven at the second current.