MRI Technical Terms
Boot Terminal The primary login terminal on the host computer used to start scanner software
Chiller 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.
Cryogens Supercooled liquids that are used to keep magnets at super conducting temperatures. Most magnets use Liquid Helium (LHe) and some use both liquid nitrogen (LN2) and LHe.
Cryogen Meter Sometimes called helium meter or nitrogen meter is used to monitor the cryogen level of Lhe or LN2 used in the magnet.
Dewar A large vacuum jacketed (double walled container) generally made out of stainless steel that is used to transport cryogens.
Ferrous or Ferromagnetic A material containing iron having a magnetic property that produces a strong and powerful attraction between that object and the center of the magnet.
Gradient The magnitude and direction of the rate of change in space of the magnetic field strength. In a MR system gradient amplifiers and coils are used to vary the magnetic field strength in the X, Y, and Z planes.
Homogeneity Refers to the uniformity or consistency in the magnetic field. Proper homogeneity is required for optimum images.
Penetration Panel This is the point of penetration of the MR system cables into the RF room. This panel contains filters and other connections required provide communication between the scan room and the rest of the system without allowing interference to pass.
Ramp To energize or bring the magnet up to field
Ramp Supply A DC power supply used ramp the magnet up to field
Shield Cooler A water-cooled refrigeration system or heat pump used to reduce the shield temperatures of magnet Lhe or LN2 vessels. Lower shield temperatures reduce costly magnet boil off.
Shim Coils Coils used to compensate for inhomogeneity (inconsistency) in the in the magnetic field caused by on site ferrous objects, impurities in the magnet and inconsistencies in magnet windings.
Shimming The process of adjusting the magnetic field for inhomogeneities. There are four types: gradient, passive, resistive, and superconductive shimming
Daily Quality Assurance (DQA) A scan or procedure used by system operators to verify system operation.