ACTIVE ACOUSTIC SCREENING - REDUCTION OF NOISE IN GRADIENT COILS BY LORENTZ FORCE BALANCING

We hate designed and constructed a quiet gradient set with restricted access for the combined purposes of evaluating the principles of activ e acoustic screening, recently introduced by Mansfield, Glover, and Bo wtell, and for EPI studies of the head at 3.0 T. The design utilizes t he return paths of the conductors in a closed are loop arrangement to eliminate net Lorentz forces thereby attenuating acoustic noise especi ally at low frequency. This design should significantly reduce the dan gers to patients of high noise levels, especially in high field magnet ic resonance imaging systems.