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 method of designing a parallel transmission radio frequency (RF) pulse for a magnetic resonance imaging (MRI) system includes compressing a model for a subject to be scanned by the MRI system into a plurality of virtual observation points within the model based on comparisons of peak sensitivity to local specific absorption rate (SAR), and defining the parallel transmission RF pulse that minimizes a weighted average of local SAR values with an iterative procedure that optimizes a set of weighting factors for the plurality of virtual observation points to maximize the minimized weighted average.

Abstract: A controller of a magnetic resonance system outputs a low frequency base signal to a conversion device. While outputting the base signal to the conversion device, the controller outputs an oscillator control signal to an oscillator. The oscillator outputs a frequency signal corresponding to the oscillator control signal to the conversion device. The conversion device converts the frequency signal into a high frequency transmit pulse with the aid of the base signal and outputs the transmit pulse to a magnetic resonance transmit antenna. The magnetic resonance transmit antenna applies a high frequency field corresponding to a transmit pulse to an examination volume of the magnetic resonance system. The controller varies the oscillator control signal output to the oscillator while outputting the base signal to the modulator. The transmit pulse) has a larger bandwidth than the base signal.

Abstract: A method for determining a magnetic resonance system control sequence that includes a multichannel pulse with a plurality of individual RF pulses to be transmitted in parallel by a magnetic resonance system via different independent RF transmit channels is provided. Using a predefined target magnetization, a multichannel pulse is determined in an RF pulse optimization method. Pulse shapes of the RF pulses for the different RF transmit channels are each described by a linear combination of trial functions. Coefficients of the linear combinations of trial functions are determined in the RF pulse optimization method.

Abstract: A method for checking a high-frequency transmit device of a magnetic resonance tomography system, excitation vectors that represent high-frequency signal strengths on the individual transmit channels are determined for a plurality of time points or time periods. High-frequency exposure values absorbed in an examination object are determined in accordance with predetermined check rules on the basis of the excitation vectors. The high-frequency transmit device is restricted in function when an exposure check value that is based on at least one high-frequency exposure value reaches or exceeds a predetermined limit check value. The check rules are predetermined as a function of a current transmit mode of the high-frequency transmit device. The respective transmit mode of the high-frequency transmit device is verified on the basis of the excitation vectors. When a transmit mode change is detected, the check rules are changed, and/or the high-frequency transmit device is restricted in function.

Abstract: A device for detecting signals is disclosed. In at least one embodiment, the device includes at least four detector elements for receiving the signals and converting them into useful signals, each being connected via at least two lines to at least one signal processing unit. Each detector element includes a polarity reversal unit by which polarity reversal of the useful signal of the respective detector element can be performed. The signal polarity reversal logic is unambiguously spatially direction-dependent within the detector array. An advantage of the device of at least one embodiment is that for signals to be received simultaneously by way of two detector elements, the detector elements involved become unambiguously identifiable by the polarity reversal of the useful signal.

Abstract: A method and a control sequence determination device for determining a magnetic resonance system control sequence are described. The magnetic resonance system control sequence includes a multichannel pulse train having a plurality of individual RF pulse trains that are to be transmitted in parallel by the magnetic resonance system over different independent radio-frequency transmit channels. The multichannel pulse train is calculated on the basis of a predefined target function with a predefined target magnetization in an RF pulse optimization method, where the target function is predefined such that the target function includes at least one local RF exposure value of an examination subject that is dependent on the control sequence. Also described are a method for operating a magnetic resonance system and a magnetic resonance system including the control sequence determination device.

Abstract: Sensitivity matrices are determined for hotspots, the sensitivity matrices being used in the determination of control signal sequences for individually-controllable antenna elements of a radio-frequency transmit system of a magnetic resonance tomography device. For each hotspot, an SAR element may be established by summing the products of the elements of the respective sensitivity matrix with the corresponding elements of a cross-correlation matrix. A computer groups voxels of an object defined by a plurality of voxels into clusters. The computer assigns each cluster to one of the hotspots. For each hotspot, the computer establishes the respective sensitivity matrix such that in relation to each voxel of the cluster assigned to the respective hotspot, the difference between the sensitivity matrix established for the respective hotspot and a sensitivity matrix given for the respective voxel is positive semi-definite.

Abstract: In a device and a method to determine SAR for a magnetic resonance tomography transmission system with multiple antenna elements, a single-column cross-correlation matrix of an antenna element matrix of antenna element values of multiple antenna elements of the magnetic resonance tomography transmission system is determined for each of multiple points in time or time periods. These single-column cross-correlation matrices are added into a sum cross-correlation matrix over a summation time period and the sum cross-correlation matrix is multiplied with a hotspot sensitivity matrix. The hotspot sensitivity matrix represents the sensitivities in at least one direction at a number of hotspot points in a subject located in the magnetic resonance tomography transmission system. The product of the sum cross-correlation matrix and the hotspot sensitivity matrix is multiplied with a value representing the dielectricity at least one hotspot point in order to determine a respective SAR value for hotspot points.

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 scanner including a PET unit includes a magnet system and a gradient system having a patient bore. In at least one embodiment, the magnet system and the gradient system are each split by an azimuthal gap and the PET unit is disposed within the gap.

Abstract: A device for detecting signals is disclosed. In at least one embodiment, the device includes at least four detector elements for receiving the signals and converting them into useful signals, each being connected via at least two lines to at least one signal processing unit. Each detector element includes a polarity reversal unit by which polarity reversal of the useful signal of the respective detector element can be performed. The signal polarity reversal logic is unambiguously spatially direction-dependent within the detector array. An advantage of the device of at least one embodiment is that for signals to be received simultaneously by way of two detector elements, the detector elements involved become unambiguously identifiable by the polarity reversal of the useful signal.

Abstract: A generator of time-variable magnetic fields generator for a magnetic resonance apparatus has a primary gradient coil unit for generating of a gradient magnetic field in an examination region of the magnetic resonance apparatus. The primary gradient coil unit, for accommodating at least one gradient coil conductor, has a central region, an outer region and at least one connecting region connecting the two regions. The outer region surrounds the central region. At least one intervening space is disposed between the central region and the outer region. The intervening space is free of the gradient coil conductors of the primary gradient coil unit and a radio frequency antenna element is disposed therein. Such a generator enables an effective gradient field and RF field generation in a compact design combining a gradient coil and a radio-frequency antenna.

Abstract: A gradient coil radio-frequency antenna unit for a magnetic resonance apparatus has a radio-frequency antenna and a plate-shaped gradient coil unit to generate a gradient magnetic field in an examination region of the magnetic resonance apparatus. The gradient coil unit is surrounded by a conductor of the radio-frequency antenna. The windings of the gradient coil unit thus lie completely within the conductor of the RF antenna.

Abstract: A generator of time-variable magnetic fields generator for a magnetic resonance apparatus has a primary gradient coil unit for generating of a gradient magnetic field in an examination region of the magnetic resonance apparatus. The primary gradient coil unit, for accommodating at least one gradient coil conductor, has a central region, an outer region and at least one connecting region connecting the two regions. The outer region surrounds the central region. At least one intervening space is disposed between the central region and the outer region. The intervening space is free of the gradient coil conductors of the primary gradient coil unit and a radio frequency antenna element is disposed therein. Such a generator enables an effective gradient field and RF field generation in a compact design combining a gradient coil and a radio-frequency antenna.

Abstract: A gradient coil radio-frequency antenna unit for a magnetic resonance apparatus has a radio-frequency antenna and a plate-shaped gradient coil unit to generate a gradient magnetic field in an examination region of the magnetic resonance apparatus. The gradient coil unit is surrounded by a conductor of the radio-frequency antenna. The windings of the gradient coil unit thus lie completely within the conductor of the RF antenna.

Abstract: A magnetic resonance apparatus has a receptacle space for the acceptance of at least one carrier device equipable with shim elements and at least one hollow member for conducting a coolant that cools the shim elements, a carrier device equipable with shim elements is designed forming at least one hollow member for conducting a coolant that cools the shim elements.

Abstract: A magnetic resonance apparatus has a receptacle space for the acceptance of at least one carrier device equipable with shim elements and at least one hollow member for conducting a coolant that cools the shim elements, a carrier device equipable with shim elements is designed forming at least one hollow member for conducting a coolant that cools the shim elements.

Abstract: A magnetic resonance apparatus has a basic field magnet system for generating a basic magnetic field and a coil system with a coil arrangement, wherein a course of a current-carrying conductor of the coil arrangement for generating a predetermined target magnetic field is determined according to a method that allows for linear secondary conditions. A noise-causing mechanical oscillation of the coil system as a result of Lorentz forces that act on the current-carrying conductor in the basic magnetic field is thereby taken into consideration by one of the linear secondary conditions, and the course of the conductor is additionally determined by the method so that the noise-causing oscillation is diminished.