Method and device for determining a magnetic resonance system control sequence

A method for operating a magnetic resonance system, the magnetic resonance system comprising a plurality of independent radio-frequency transmit channels, the method comprising:

• obtaining a magnetic resonance control sequence, wherein the magnetic resonance control sequence comprises a multichannel pulse train optimized on the basis of a predefined target function with a predefined target magnetization;
• transmitting the multichannel pulse train, the multichannel pulse train having a plurality of individual RF pulse trains, wherein the plurality of individual RF pulse trains is transmitted in parallel by the magnetic resonance system over different independent radio-frequency transmit channels;
• and
• operating the magnetic resonance system using the magnetic resonance control sequence,
• wherein the predefined target function is predefined such that the predefined target function includes a local RF exposure value of an examination subject that is dependent on the magnetic resonance control sequence.

A control sequence determination device for determining a magnetic resonance system control sequence, the magnetic resonance system control sequence comprising 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 control sequence determination device comprising:

• an input interface configured to acquire a target magnetization;
• an RF pulse optimization unit configured to calculate the multichannel pulse train on the basis of a predefined target function with a predefined target magnetization in an RF pulse optimization;
• and
• a control sequence output interface,
• wherein the control sequence determination device is configured to use the predefined target function, the predefined target function including a local RF exposure value of an examination subject that is dependent on the control sequence in the RF pulse optimization.

A magnetic resonance system comprising a plurality of independent radio-frequency transmit channels, the magnetic resonance system comprising:

• a gradient system and a control device, the control device being configured for transmitting a multichannel pulse train comprising a plurality of parallel individual RF pulse trains over the plurality of independent radio-frequency transmit channels to perform a desired measurement on the basis of a predefined control sequence;
• and
• a control sequence determination device configured to determine the predefined control sequence and pass the predefined control sequence on to the control device, the control sequence determination device comprising:
• an input interface configured to acquire a target magnetization;
• an RF pulse optimization unit configured to calculate the multichannel pulse train on the basis of a predefined target function with a predefined target magnetization in an RF pulse optimization;
• and
• a control sequence output interface,
• wherein the control sequence determination device is configured to use the predefined target function, the predefined target function including a local RF exposure value of an examination subject that is dependent on the control sequence in the RF pulse optimization.

In a non-transitory computer readable medium comprising computer readable instructions that, when executed by a control sequence determination device, cause the control sequence determination device to perform a method for determining a magnetic resonance system control sequence, the instructions comprising:

• calculating a multichannel pulse train in an RF pulse optimization on the basis of a predefined target function with a predefined target magnetization;
• and
• transmitting the multichannel pulse train, the multichannel pulse train having a plurality of individual RF pulse trains, wherein the plurality of individual RF pulse trains is transmitted in parallel by the magnetic resonance system over different independent radio-frequency transmit channels,
• wherein the predefined target function is predefined such that the predefined target function includes a local RF exposure value of an examination subject that is dependent on the magnetic resonance control sequence.