Abstract: The embodiments relate to a method and a device for spatial homogenization of the field strength of voltages of radiofrequency pulses of a number of RF transmitters, wherein (a) the measured complex voltages, induced by the electromagnetic field of the antenna, of a plurality of field probes, which are disposed in the vicinity of the antenna, are respectively superposed with a fitting phase shift and used for establishing the new desired homogenized voltages of the radiofrequency pulses of the antenna by a complex transfer function, and/or (b) output signals of at least two directional couplers on the RF feed lines of the antenna are superposed in a respectively fitting phase-shifted manner and these are used to establish complex impedances or scattering parameters of a complex scattering matrix of the antenna, which are used for establishing the new desired homogenized voltages of the radiofrequency pulses of the antenna.

Abstract: The present embodiments relate to a standing wave trap for a magnetic resonance tomography device. The standing wave trap includes a conductor region extending in one plane and at least one capacitor that is conductively connected to two sections of the conductor region.

Abstract: The embodiments relate to a magnetic resonance coil for a magnetic resonance device with a measuring chamber for an examination object and a cylindrical birdcage antenna arrangement having a plurality of antenna elements disposed at least in some areas around a measuring chamber in the form of circumferential antenna rings or axial outer rods connecting the rings. The antenna elements include electric components, e.g., reactive capacitive and/or inductive systems. The magnetic resonance coil also has at least two antenna feeds, e.g., phase-offset in relation to one another by 90°, by which radio-frequency energy is able to be supplied to the birdcage antenna arrangement. The antenna feeds include at least one symmetrical feed via at least one of the electric components of the birdcage antenna arrangement as well is at least one assigned asymmetrical feed between the birdcage antenna arrangement and a screen connection.

Abstract: A monitoring method to monitor and/or protect modules, in particular a radio-frequency antenna of a magnetic resonance system, includes a measurement step in which at least one first characteristic monitoring variable is measured by at least one first measurement unit, and at least one calculation step in which at least one maximum limit value for a power and/or a voltage within the module is calculated using the at least one first measured characteristic monitoring variable. At least one second characteristic monitoring variable, different than the at least one first characteristic monitoring variable, is measured in the measurement step.

Abstract: An antenna array for a magnetic resonance tomography system includes a first ring with a plurality of first capacitors, a second ring with a plurality of second capacitors, and a plurality of antenna rods each extending from a region between two adjacent first capacitors to a region between two adjacent second capacitors. The antenna array enables, as a body coil, a multi-channel reception for use of modern imaging methods with a low level of technical complexity. An antenna rod of the plurality of antenna rods comprises a decoupling module configured to decouple, as required, the respective antenna rod from the remaining antenna rods of the plurality of antenna rods.

Abstract: The present embodiments include a magnetic resonance antenna having parallel-running longitudinal antenna rods arranged in a birdcage structure and antenna ferrules connecting the parallel-running longitudinal antenna rods at ends of the parallel-running longitudinal antenna rods in radio frequency terms. The magnetic resonance antenna includes a plurality of radio-frequency switching elements configured to interrupt at least a part of the parallel-running longitudinal antenna rods to detune a natural resonance frequency with respect to an operating magnetic resonance frequency in radio frequency terms. At least some radio-frequency switching elements of the plurality of radio-frequency switching elements are arranged at end sections of the parallel-running longitudinal antenna rods.

Abstract: A magnetic resonance device with a measurement chamber, an antenna arrangement that has a plurality of antenna elements arranged at least in certain areas around the measurement chamber, a gradient coil system arranged outside the antenna arrangement as seen from the measurement chamber, and a high-frequency shield system arranged between the antenna arrangement and the gradient coil system are provided. The high-frequency shield system has a reflector array with a plurality of passive reflector resonance circuits, each of which is configured such that resonance frequencies of the plurality of passive reflector resonance circuits lie below an operating magnetic resonance frequency of the magnetic resonance device and that the plurality of passive reflector resonance circuits has an inductive overall impedance.

Abstract: A transmit coil arrangement for a magnetic resonance device includes a plurality of individually actuatable conductor loops following one after another in a peripheral direction and a longitudinal direction on a cylinder surface. At least two groups, at a distance from one another in the peripheral direction, of at least two conductor loops following one after the other in the longitudinal direction are provided in the peripheral direction. To decouple the at least two groups, each of the at least two groups is bounded at least in the peripheral direction by at least one screen surface extending essentially in a radial direction and the longitudinal direction.

Abstract: An antenna arrangement for magnetic resonance applications includes antenna elements substantially parallel to a common central axis, distributed around the central axis at a distance from the central axis, and enclosing an essentially cylindrical volume. The antenna arrangement includes intermediate connections that connect to immediately adjacent antenna elements at connection points that lie between the ends of the antenna elements. A preamplifier connects to each of the intermediate connections and has an output that, in a receive mode, corresponds to a respective feed-out point. In send mode, the antenna arrangement injects radio-frequency signals into the antenna elements using the injection points. The antenna arrangement is also configured to adjust the intermediate connections to a higher resistance when the antenna arrangement is in the send mode and at least some of the intermediate connections to a lower resistance when the antenna arrangement is in the receive mode.

Abstract: A whole-body coil for a magnetic resonance tomography device includes one or more compensation capacitors between a high-frequency antenna and an RF shield. The one or more compensation capacitors each have variable capacitance caused by a variation in a distance of the RF shield to the high-frequency antenna.

Abstract: A B1 magnetic field may be regulated during a magnetic resonance tomography (MRT) imaging sequence.

Abstract: A method for monitoring an exposure experienced by a patient during an examination with a magnetic resonance device having a transmitter device is provided. The method includes determining a coil power loss from measured amplitudes and phases of a first measuring device, and determining an overall transmitted power from voltage measurement values of the second measuring device. The method also includes determining a specific absorption rate (SAR) value describing a power entering a patient from the coil power loss and the overall transmitted power and comparing the SAR value with at least one limit value. A transmission operation of the transmitter device is terminated if the at least one limit value is exceeded.

Abstract: In a method and a device for specific absorption rate monitoring in a magnetic resonance system wherein multiple transmit coils are independently charged with respective currents, a primary model point voxel and at least one auxiliary model point voxel are automatically selected from among multiple voxels that model a modeled examination subject. The primary model point voxel is that voxel in which an absolute maximum of a total field variable occurs that is produced by the respective electrical fields emitted by the transmit coils. The at least one auxiliary model point voxel is that voxel in which a relative maximum of the variable occurs.

Abstract: A magnetic resonance antenna arrangement includes at least one first antenna group including individually-controllable first antenna conductor loops and a second antenna group adjacent to the first antenna group. The second antenna group includes individually-controllable, longitudinal second antenna elements. The first antenna conductor loops essentially extend in a first extending surface and are disposed in the first extending surface in a first direction in a row behind one another. The longitudinal second antenna elements extend with the longitudinal axes transverse to the first direction disposed in parallel next to one another in a second extending surface that runs essentially in parallel to the first extending surface. Each of the second antenna elements are coupled at first and second end areas to a conductive element to form a second conductor loop with the conductive element. The second antenna elements are disposed to overlap an adjacent first antenna loop in each case.

Abstract: In a device for monitoring a radio-frequency transmit device of a magnetic resonance system, having a transmitter antenna system that has a number of transmit channels, a reference scattering parameter matrix of the transmitter antenna system is determined in the unloaded state with no subject present, and a subject-specific scattering parameter matrix of the transmitter antenna system is determined in a state loaded with the subject. time-dependent transmitter amplitude vectors are determined that represent the radio-frequency voltage amplitudes on the individual transmit channels. From the subject-specific scattering parameter matrix, the reference scattering parameter matrix, and the transmit amplitude vectors, radio-frequency power values absorbed at particular transmit times in the subject are determined, from which monitoring values are formed that, when reached, cause operation of the radio-frequency transmit device to be limited during acquisition of magnetic resonance data.

Abstract: A method determines an optimal structure of a high-frequency shield of a high-frequency antenna of a magnetic resonance arrangement. The high-frequency shield shields the high-frequency antenna from a gradient-coil arrangement. A three-dimensional initial structure of the high-frequency shield is defined in accordance with structural parameters and jointly with the high-frequency antenna, the gradient-coil arrangement, or both the high-frequency antenna and the gradient-coil arrangement. The structural parameters are optimized via an optimization method with respect to at least one optimization criterion.

Abstract: A method for the control of a magnetic resonance system is provided. In a test phase before a magnetic resonance measurement, a test high-frequency pulse with several parallel individual high-frequency pulses is transmitted with a transmitter antenna arrangement over various different high-frequency transmitter channels. At lower transmitter power, the test high-frequency pulse generates essentially the same field distribution as an excitation high-frequency pulse to be transmitted during a subsequent magnetic resonance measurement. A high-frequency field generated by this test high-frequency pulse is measured in at least one area of a local pulse arrangement, and on the basis of the high-frequency field measured, a high-frequency field value that is to be anticipated at the local coil arrangement during the subsequent magnetic resonance measurement is determined.

Abstract: A magnetic resonance system obtaining magnetic resonance exposures of an examination subject, has an examination tunnel, a whole-body antenna with two connection terminals. The whole-body antenna cylindrically extends around the examination tunnel along a longitudinal axis. The system has a radio-frequency supply device in order to respectively supply the whole-body antenna with radio-frequency signals for emission of a radio-frequency field in the examination tunnel. The radio-frequency supply device has a radio-frequency generator for generation of a radio-frequency signal, a signal splitter that divides a radio-frequency signal coming from the radio-frequency generator into two partial signals that are phase-shifted by 90° relative to one another. Two radio-frequency feed lines are connected with the two connection terminals of the whole-body antenna. Via these radio-frequency feed lines, the two partial signals are fed into the whole-body antenna.

Abstract: The efficiency and the field structure of an antenna arrangement for a magnetic resonance tomography apparatus are improved by at least one impedance transformation circuit connected with the antenna.

Abstract: A patient support apparatus for a medical imaging apparatus, such as a magnetic resonance apparatus, is proposed. The patient support apparatus has a couch, a lifting unit for vertical movement of the couch, a travel unit, and at least one sensor unit to detect at least one weight variable for determining the weight of a patient. The at least one sensor unit has at least one sensor element, which is disposed on the lifting unit and/or on the travel unit.