4 results about "Field homogeneity" patented technology

The application discloses a traveling wave antenna unit, an array and a method for improving high-field magnetic resonance radio frequency field uniformity, relates to the field of magnetic resonance imaging, and aims to improve high-field magnetic resonance radio frequency field uniformity. The application increases the component of the wave number of the traveling wave antenna unit in the traveling wave transmission line direction in the traveling wave antenna array through physical or chemical means to relieve the radial standing wave effect. The traveling wave antenna unit comprises a layer-by-layer designed metal microstrip, a first bearing substrate, a filling layer substrate, a slotted metal floor, a second bearing substrate and a spacing layer substrate. A feeding port is connected between the first end of the metal microstrip and the slotted metal floor, and a load is connected between the second end of the metal microstrip and the slotted metal floor. The filling layer substrate is a fillable structure. The component in the traveling wave transmission line direction is increased by increasing the relative dielectric constant of the filling medium or changing the slotted structure. The application is simple in design, convenient in operation and does not need additional hardware.

Systems and methods are provided for a hybrid superconducting-permanent magnet MRI system. Permanent magnet elements may be used to supplement or shape the magnetic field produced by the superconducting windings. The hybrid design may increase field homogeneity or reduce the required bore length, thereby reducing the total system cost.

The invention discloses a magnetic resonance radio frequency shimming optimization method and device based on spatial weight and adaptive reweighting. The magnetic resonance radio frequency shimming optimization method based on spatial weight and adaptive reweighting comprises the following steps: acquiring excitation field distribution to be optimized; obtaining a target area excitation magnetic field matrix, a peripheral area excitation magnetic field matrix and a target function according to the to-be-optimized excitation field distribution; according to the target area excitation magnetic field matrix, the peripheral area excitation magnetic field matrix and a target function, through an iteration adaptive reweighting mechanism, dynamically updating a peripheral weight so as to generate a final channel complex weight; and transmitting the final channel complex number weight to a magnetic resonance emission system, thereby enabling the magnetic resonance emission system to realize radio frequency shimming according to the final channel complex number weight. Through the generated final channel complex weight, the peripheral response can be balanced while the performance of the target region is ensured, and the uniformity control of the B1 + field of each region is realized.

2.1. The invention relates to a device for generating a highly homogeneous magnetic field within a measurement volume using permanent magnets. Small to medium fields in the microtesla to the tens of millitesla range are to be generated in a measurement volume with good accessibility. An arrangement of two rings with Halbach magnetization, positioned axially at a defined distance, theoretically achieves good homogeneity, but limits access to the measurement volume and is difficult to implement in practice. The invention was therefore based on the objective of realizing a device with the highest possible homogeneity while maintaining a simple design. 2.2. The invention describes a device in which only four magnets are fixed on an axis. The magnets are arranged in identical pairs and symmetrically around the measuring volume. The distances to the center of the measuring volume are related to the respective magnetic moments in a manner specified by the invention. Instead of individual magnets, magnetic fields can also be applied to one or two magnetizable bodies. 2. 3. With the device according to the invention, good field homogeneity is achieved over a given measuring volume with only four magnets and with good accessibility of the measuring volume, for example for electronic sensor setups.