Siemens Aktiengesellschaft

Siemens Healthcare Gmbh

Siemens Aktiengesell Schaft

Wolfgang Bielmeier

Matthias Gebhardt

Gerhard Brinker

Markus Vester

Dominik Paul

Swen Campagna

Klaus Ludwig

Carsten Prinz

Gudrun Ruyters

Bernd Erbe

Jürgen Nistler

Nikolaus Demharter

Juergen Nistler

Volker Schnetter

Stephan Stoecker

Stephan Stöcker

Dieter Ritter

Helmut Lenz

Joerg Roland

Diana Martin

Miriam Keil

In a magnetic resonance apparatus and a method for operation thereof, at least one electrical operating value of at least one predetermined component of the apparatus is captured and, as a function of the at least one operating value, at least one coil operating value of a transmitting coil arrangement of the magnetic resonance apparatus is controlled for the purpose of limiting a B1 value.

Magnetic resonance apparatus and operating method therefor with monitoring and control of RF energy-relevant operating value

The disclosure relates to a method for monitoring an absorption rate when using a primary coil of a magnetic resonance device and a secondary coil inductively coupled to the primary coil and to a monitoring unit, a magnetic resonance device and a computer program product. According to the method a maximum admissible absorption rate is provided, using which a maximum admissible B1 field strength of the secondary coil is determined. Furthermore, an actual B1 field strength of the secondary coil is determined. The absorption rate is monitored using the actual B1 field strength of the secondary coil and the maximum admissible B1 field strength of the secondary coil.

Monitoring an absorption rate of inductively coupled coils

A method for monitoring a temporal change in a magnetic field in a magnetic resonance device, as well as an evaluation unit, a magnetic resonance device, and a computer program product for performing the method are provided. The method provides that a position-dependent magnetic field distribution that is produced by the plurality of gradient coils is provided with a plurality of monitoring points. In addition, time-dependent gradient values of the plurality of gradient coils are ascertained. Based on position-dependent magnetic field distribution and the time-dependent gradient values, the temporal change in the magnetic field is ascertained. The temporal change in the magnetic field is monitored by comparing the temporal change in the magnetic field with at least one limit value.

Monitoring of a temporal change in a magnetic field in a magnetic resonance device

In a magnetic resonance (MR) apparatus and an operating method therefor, a sequence with which the MR data are to be recorded is created in or provided to a control computer of the MR apparatus. A maximum RF output and a maximum gradient performance of the scanner magnetic resonance apparatus during the performance of the sequence are determined by simulating or analyzing the performance of the sequence in the control computer, and it is verified whether the maximum RF output and/or the maximum gradient performance violate predetermined limit values. Execution of the sequence to record the MR data is performed only if the verification showed that the limit values are not violated.

Method and magnetic resonance apparatus wherein limit values are observed when recording magnetic resonance data

In a magnetic resonance apparatus and an operating method therefor in which magnetic resonance data are acquired from a patient, a measurement process is used in which a number of magnetic resonance sequences are carried out sequentially, and a maximum measurement time parameter, describing a maximum possible measurement time for undershooting a threshold value for the overall energy input into the patient during the measurement process, is established, taking into account other known recording parameters of the measurement process. The maximum measurement time parameter is used to restrict the ability of an operator to set a measurement time parameter describing the measurement time as a recording parameter, and/or is used as the measurement time parameter.

Magnetic resonance apparatus and operating method

A method for operating a magnetic resonance apparatus by a safety unit, taking into account persons fitted with an implant, a safety unit, a safety system, a magnetic resonance apparatus, and a computer program product are provided. The magnetic resonance apparatus includes a first part and a second part. The first part is operated separately from the second part and includes the safety unit. During an examination of a person fitted with an implant, the safety unit checks that the magnetic resonance apparatus, in a restricted operating mode, is complying with implant-conformant limit values.

Operation of a magnetic resonance apparatus taking into account persons fitted with implants

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.

Method for monitoring patient exposure in a magnetic resonance device

A method is disclosed for determining at least one PET parameter for a PET examination in a combined magnetic resonance/PET scanner designed for isocentric measurement. In at least one embodiment, at least one acquisition time for the PET examination is determined as a PET parameter from magnetic resonance data, recorded for determining patient-specific examination parameters for a magnetic resonance examination, and/or from at least one patient-specific information value derived therefrom, and is displayed and/or used for controlling the scanner.

Method for determining at least one pet parameter

In a method for monitoring a radio-frequency power amplifier, and a radio-frequency device, and a radio-frequency monitoring device and a magnetic resonance tomography system, radio-frequency pulses are emitted at temporal intervals by the radio-frequency power amplifier, and measurement values that represent the power of the radio-frequency pulses are measured at temporal intervals. The measurement values are respectively loaded with a measurement error. Control values are respectively formed based on the sum of a number of measurement values loaded with measurement errors, and the radio-frequency power amplifier is limited in operation if and when a control value reaches or exceeds a predetermined limit control value.

Method for monitoring an RF power amplifier, and an RF device, a monitoring device, and an MR system corresponding thereto

In a method, device and magnetic resonance tomography system for monitoring a radio-frequency apparatus in which radio-frequency pulses are emitted at temporal intervals and in which measurement values representing the power of the radio-frequency pulses are measured at temporal intervals, the measurement values are used to determine exposure values that represent a physiological effect that the radio-frequency pulses have on a subject exposed to the radio-frequency pulses. Based on a number of exposure values, exposure-monitoring values are respectively formed and the radio-frequency apparatus is limited in function if an exposure-monitoring value reaches or exceeds an exposure limit value.

Method, device and magnetic resonance tomography system for monitoring emitted RF energy

In a method for monitoring of a radio frequency power amplifier and a radio frequency device, a radio frequency monitoring device and magnetic resonance tomography system operable according to the method, radio frequency pulses emitted by a radio frequency power amplifier and are transmitted into a human subject by a transmission coil at temporal intervals. Measurement values that represent the power of the radio frequency pulses are measured at temporal intervals, and varying, predetermined power limit values are determined at temporal intervals. A control value representing the radio frequency dose emitted in a time window is determined based on a number of measurement values measured in the time window. Likewise, a limit control value representing a dose limit value allowed in the appertaining time window is determined based on the power limit values determined in the appertaining time window. The radio frequency power amplifier is limited in operation if and when the control value reaches or exceeds the limit control value.

In a method for controlling a radio-frequency device, and a magnetic resonance tomography system and a radio-frequency control device wherein the method is implemented, the RF device of a magnetic resonance tomography system is emitted during a magnetic resonance measurement of an examination subject that is moving relative to the transmission field of the RF device. The RF device emits RF pulses at chronological intervals, and measurement values are measured at chronological intervals. At chronological intervals, position values are determined that represent a current position of the examination subject relative to the transmission field. On the basis of the measurement values and the position values, exposure values are determined that represent a physiological degree of effectiveness that the RF pulses have on the subject exposed to the RF pulses. Based on a multiplicity of exposure values, exposure control values are respectively formed. The RF device is limited in its functioning if an exposure control value reaches or exceeds an exposure limit value.

Growing community of inventors

Erlangen, Germany

Wolfgang Bielmeier