A refrigeration unit that supplies cold water used to cool MRI components. Depending on the system configuration chillers are used to cool shield coolers, shim coils and sometimes the air conditioning.
A coil consists of one or more loops of conductive wire, looped around the core of the coil. Coils are part of the hardware of MRI machines and are used to create a magnetic field or to detect a changing magnetic field by voltage induced in the wire. A coil is usually a physically small antenna. The perfect coil produces a uniform magnetic field without significant radiation. Different types of MRI coils are used in MR systems:
Gradient coils are used to produce controlled variations in the main magnetic field (B0) to provide spatial localization of the signals and to apply reversal pulses in some imaging techniques.
MR imaging radio frequency coils to receive and/or transmit the RF signal.
Shim coils provide auxiliary magnetic fields in order to compensate for inhomogeneities in the main magnetic field of the MRI machine.
See also Gradient Coil, Radio Frequency Coil, Hardware and Coil Loading.