Patent ID: 6853855
Filing Date: 2005-02-08
Classification: G01R

Abstract:
1. A magnetic resonance apparatus comprising: a basic field magnet which generates a uniform basic magnetic field; a gradient coil system for encoding signals within said basic magnetic field; a passive shim system having a plurality of shim iron plates disposed to interact with said basic field magnet to homogenize said basic magnetic field; and a thermal control device comprising a bridge circuit containing transistors, operatonal amplifiers and a Peltier element in thermal communication with at least one of said shim iron plates, and a temperature regulating circuit, connected to said bridge circuit, for generating an output signal for regulating a temperature of said at least one of said shim iron plates, said output signal switching said transistors for selectively placing said Peltier element in one of an operating mode for elevating the temperature said at least one of the shim iron plates or a mode for decreasing the temperature said at least one of the shim iron plates.