Control of a radio-frequency amplifier of a magnetic resonance system

A method for control of a radio-frequency amplifier of a magnetic resonance system, the method comprising:

• determining a radio-frequency power to be output by the radio-frequency amplifier during an examination of a patient in the magnetic resonance system;
• determining a temperature curve over time in tissue of the patient, the tissue curve comprising at least one preceding temperature in the tissue at a preceding point in time and a current temperature in the tissue at a current point in time, wherein the current temperature is determined as a function of the preceding temperature and as a function of the radio-frequency power at the current point in time;
• and
• setting the radio-frequency amplifier as a function of the temperature curve.

A magnetic resonance system comprising:

• a gradient field system;
• a radio-frequency antenna;
• a radio-frequency amplifier that is coupled to the radio-frequency antenna for output of a radio-frequency signal;
• and
• a controller configured to:
• control the gradient field system and the radio-frequency amplifier;
• receive measurement signals recorded by the radio-frequency antenna;
• evaluate the measurement signals;
• create magnetic resonance data,
• wherein the magnetic resonance system is configured to:
• determine a radio-frequency power to be output by the radio-frequency amplifier during an examination of a patient in the magnetic resonance system;
• determine a maximum temperature in tissue of the patient as a function of the radio-frequency power using a Lambert W function;
• and
• set the radio-frequency amplifier as a function of the maximum temperature.

A magnetic resonance system comprising:

• a gradient field system;
• a radio-frequency antenna;
• a radio-frequency amplifier that is coupled to the radio-frequency antenna for output of a radio-frequency signal;
• and
• a controller configured to:
• control the gradient field system and the radio-frequency amplifier;
• receive measurement signals recorded by the radio-frequency antenna;
• evaluate the measurement signals;
• and
• create magnetic resonance data,
• wherein the magnetic resonance system is configured to:
• determine a radio-frequency power to be output by a radio-frequency amplifier of the magnetic resonance system during an examination of a patient in the magnetic resonance system;
• determine a temperature curve over time in tissue of the patient, the temperature curve comprising at least one preceding temperature in the tissue at a preceding point in time and a current temperature in the tissue at a current point in time, wherein the current temperature is determined as a function of the preceding temperature and as a function of the radio-frequency power at the current point in time, and
• set the radio-frequency amplifier as a function of the temperature curve.

In a non-transitory computer-readable storage medium that stores instructions executable by a controller of a magnetic resonance system to control a radio-frequency amplifier of the magnetic resonance system, the instructions comprising:

• determining a radio-frequency power to be output by the radio-frequency amplifier during an examination of a patient in the magnetic resonance system;
• determining a maximum temperature in tissue of the patient as a function of the radio-frequency power using a Lambert W function;
• and
• setting the radio-frequency amplifier as a function of the determined maximum temperature.