APPARATUS FOR FORMATION OF SUBSTANTIALLY CONSTANT POLARIZING MAGNETIC FIELD OF NMR SYSTEM AND METHOD FOR COMPENSATION OF TEMPERATURE-INDUCED VARIATIONS OF STATIC POLARIZING MAGNETIC FIELD PRODUCED BY MAGNET OF MRI SYSTEM

摘要

PURPOSE: An apparatus for producing polarizing magnetic field of an NMR system and a method for compensation of image quality of the NMR system by maintaining the polarizing magnetic field at constant strength are provided. Therefore, image quality of the NMR system is improved regardless of change in temperature. CONSTITUTION: The apparatus of producing polarizing magnetic field comprises: a magnet for producing substantially static polarizing magnetic field to change strength as a function of a magnetic temperature; a device for calculating compensating flux based on the temperature owing to the response of the magnet temperature; a compensating coil for producing the calculated compensating flux to allow the sum of the calculated compensation flux and polarizing magnetic field to maintain substantially stable. The process for supplying the compensating magnetic flux comprises winding a correction coil on a part of a permanent magnet and producing the compensating magnetic flux by supplying appropriate current to the coil.