Compensation of magnetic field components caused by a periodic motion of a cold head

Abstract

The present invention provides a method for compensation of periodic Bmodulations from a periodic motion of a cold head () of a main magnet () of a magnetic resonance (MR) imaging system (), whereby main windings () of the main magnet () are cooled to superconductivity by the cold head (), which exerts a repetitive motion, the method comprising the steps of measuring a periodic occurrence of spatial field components of the B-field based on a motion of the cold head () as a function of time, performing a sensor measurement of a periodic, auxiliary parameter of the MR imaging system (), which is not the periodic occurrence of spatial field components, synchronizing the periodic occurrence of spatial field components of the B-field with the measured periodic, auxiliary parameter of the MR imaging system (), and triggering based on the measured periodic sensor measurement of the MR imaging system () a periodic application of compensation signals to compensate the periodic occurrence of spatial field components of the B-field based on a motion of the cold head (). Furthermore, the present invention provides a MR imaging system () for providing an image representation of a region of interest () of a subject of interest () positioned in an examination space () of the MR imaging system (), wherein the MR imaging system () is adapted to perform the above method.