Calibration of a magnetic resonance device and estimating a specific absorption rate

A method for estimating a specific absorption rate for an object to be examined in case of an examination with a magnetic resonance device with a transmitting device for generating an excitation field, which comprises a first transmitting coil element and at least one second transmitting coil element, wherein the first transmitting coil element is coupled to the at least one second transmitting coil element, the method comprising:

• detuning the first transmitting coil element and tuning the at least one second transmitting coil element for a first acquisition phase;
• acquiring, during the first acquisition phase, a magnetic resonance (MR) data set using the transmitting device;
• tuning the first transmitting coil element and the at least one second transmitting coil element for a second acquisition phase;
• acquiring, during the second acquisition phase, at least one further MR data set using the transmitting device;
• determining, by an arithmetic unit based on the MR data set and the at least one further MR data set, a calibration factor for calculating a total voltage value at a feeding point of the first transmitting coil element from voltage values;
• applying an excitation pulse to the object by the transmitting device;
• measuring the voltage values at the measuring point during the application of the excitation pulse;
• determining the total voltage value by the arithmetic unit based on the measured voltage values and the calibration factor;
• and
• estimating a specific absorption rate, by a specified simulation model, using the determined total voltage value as an input variable for the specified simulation model.

A magnetic resonance device comprising:

• a transmitting device having a first transmitting coil element and at least one second transmitting coil element, wherein the first transmitting coil element is coupled to the at least one second transmitting coil element, and wherein the transmitting device is configured to apply an excitation pulse to an object to be examined;
• a measuring apparatus configured to measure, during the application of the excitation pulse, voltage values at a measuring point of an electrical supply line for the first transmitting coil element;
• and
• an arithmetic unit configured to determine a total voltage value at a feeding point of the first transmitting coil element based on the measured voltage values and a specified calibration factor,
• wherein the arithmetic unit is configured to use the total voltage value as an input variable for a specified simulation model in order to determine a specific absorption rate for the object.