MAGNETIC FIELD PROBE SYSTEM WITH SYNCHRONOUS EXCITATION FOR USE IN A MAGNETIC RESONANCE IMAGING SYSTEM

摘要

A magnetic field probe system (24) for determining an actual magnetic field pattern of a magnetic resonance (MR) imaging system, comprising: at least one field probe body (26) that contains an amount of a magnetic resonance-active species of nuclei (28); a radio frequency (RF) transmit antenna (30) arranged for resonant excitation of the amount of the resonance-active species of nuclei (28); a radio frequency (RF) generator (34) provided to supply RF power to the RF transmit antenna (30); a radio frequency (RF) receive antenna (32) provided for receiving magnetic resonance RF energy emitted by the amount of the magnetic resonance-active species of nuclei (28); an RF control unit (42) provided for adjusting the RF power supplied to the RF transmit antenna (30) by using a detected value of the emitted RF energy to maintain a transverse magnetization of the amount of a magnetic resonance-active species of nuclei (28); a method of using a field probe system (24) for determining a magnetic field pattern of a magnetic resonance (MR) imaging system (10), comprising steps of arranging at least one field probe body (26) that contains an amount of a magnetic resonance-active species of nuclei (28) at a location within an examination space (16) of the MR imaging system (10); exciting the amount of the magnetic resonance-active species of nuclei (28) at a resonance frequency; acquiring a magnetic resonance RF energy emitted from the amount of the magnetic resonance-active species of nuclei (28); adjusting at least one out of phase and frequency of the applied RF power, by using a detected value of the emitted RF energy to maintain a transverse magnetization of the amount of a magnetic resonance-active species of nuclei (28); and determining a magnetic field strength at the location of the at least one field probe body (26).