In MRI systems the radio frequency (RF) transmitter produces the RF current (oscillator) and delivers it to the transmitting coil (antenna). The RF signal produced by the transmitter is used to excite the protons in the imaging volume.

Means to confine the region of strong magnetic field surrounding a magnet; most commonly the use of material with high permeability (passive shielding) or by employing secondary counteracting coils outside of the primary coils (active shielding). The high permeability material can be employed in the form of a yoke immediately surrounding the magnet (self-shielding) or installed in the walls of a room as full or partial room-shielding. Unlike shielding ionizing radiation, for example, magnetic shielding can only be accomplished by forcing the unavoidable magnetic return flux through more confined areas or structures, not by absorbing it.

See also Radio Frequency Shielding Radio Frequency Shielding, and Faraday cage.

See also the related poll result: 'Most outages of your scanning system are caused by failure of'

MRI hardware includes the electrical and mechanical components of a scanning device.
The main hardware components for the MRI machine are:
The magnet establishing the B0 field to align the spins.
Within the magnet are the gradient coils for producing variations in B0 in the X, Y, and Z directions to make a localization of the received data possible.
Within the gradient coil or directly on the object being imaged is the radio frequency (RF) coil. This RF coil is used to establish the B1 magnetic field necessary to excite the spinning nuclei. The RF coil also detects the signal emitted from the spins within the object being imaged.
The RF amplifier increases the power of the pulses.
The analog to digital converter converts the received analog raw data into digital values.
Depending on the design of the device and the body part being imaged the patient is positioned inside the magnet (e.g. on a movable table or standing upright).
The MRI scan room is surrounded by a RF shield (Faraday cage).
In addition, a computer console, a display, and a film printer belong to the MRI equipment.

See also the related poll result: 'Most outages of your scanning system are caused by failure of'

Pacemaker lead wires, ECG, and plethysmographic cables can also as surface-coil connections act as antennae. Usually the materials of such wires are not ferromagnetic.

Gradient and radio frequency fields may induce current into these wires and thus cause fibrillations and burns. This presents a risk to the patient and must be eliminated before the examination. The risk of heating during the MRI scan is dependent on the length and the material of these wires as well as the used field strength. If these wires are outside the RF field there is no risk of heating to expect.