Method and device for determining a magnetic resonance system activation sequence

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

• determining an activation sequence, the activation sequence comprising a multichannel pulse train having a plurality of individual HF pulse trains emitted in a parallel manner by the magnetic resonance system by way of different independent high-frequency transmit channels, wherein the determining comprises:
• calculating the multichannel pulse train based on a predefined target magnetization using an HF pulse optimization;
• and
• operating the magnetic resonance system using the activation sequence,
• wherein a setpoint deviation of an HF local exposure value from an HF global exposure value is optimized in the HF pulse optimization.

A control sequence determination device for determining a magnetic resonance system activation sequence, the magnetic resonance system activation sequence comprising a multichannel pulse train with a plurality of individual HF pulse trains to be emitted in a parallel manner by the magnetic resonance system by way of different independent high-frequency transmit channels, the control sequence determination device comprising:

• an input interface configured to detect a target magnetization;
• an HF pulse optimization unit configured to calculate the multichannel pulse train on the basis of a predefined target magnetization in an HF pulse optimization;
• and
• a control sequence output interface,
• wherein the HF pulse optimization unit is configured to perform an optimization with respect to a setpoint deviation of an HF local exposure value from an HF global exposure value in the HF pulse optimization.

A magnetic resonance system comprising:

• a plurality of independent high-frequency transmit channels;
• a gradient system;
• a control device configured to emit a multichannel pulse train with a plurality of parallel individual HF pulse trains by way of the plurality of independent high-frequency transmit channels to perform a desired measurement based on a predefined activation sequence;
• and
• a control sequence determination device configured to determine the predefined activation sequence and transfer the predefined activation sequence to the control device, the control sequence determination device comprising:
• an input interface configured to detect a target magnetization;
• and
• an HF pulse optimization unit configured to calculate the multichannel pulse train on the basis of a predefined target magnetization in an HF pulse optimization;
• and
• a control sequence output interface,
• wherein the HF pulse optimization unit is configured to perform an optimization with respect to a setpoint deviation of an HF local exposure value from an HF global exposure value in the HF pulse optimization.