5 RF Shielded Room Requirements
5.1 RF Shielded Room Purpose
The RF shielded room is critical to the proper clinical operation of the MR system. RF shielding
attenuates the external RF electromagnetic fields. Low RF environments present lower risk to
RF impacts to image quality. The RF shielding must also prevent the MR system RF emissions
from interfering RF receiving systems such as other MR systems, aircraft control and
communication systems.
RF shielding requirements consider the current RF environment at the site as well as future
conditions, such as expansion, with the addition or upgrade of multiple MR systems, as well as
changes to the RF environment at the time of installation. The RF shielding requirement also
considers the expected degradation over time from the RF shielded room from corrosion and
use.
The overall RF shielding performance aims to address:
1. IEC EMC Regulatory Compliance
2. MR Clinical image quality for the life of the product
5.2 RF Definitions
Broadband Interference
Broadband interference is caused by electrical discharge within the Magnet room. Potential
sources of interference can be reduced by limiting static discharge, ensuring all metal-to-metal
contact is tight and secure, and ensuring all electrical and grounding requirements are met.
Discrete Interference
Discrete interference is fixed-frequency, narrowband RF noise. Potential sources of discrete
interference are radio station transmitters and mobile RF transmitting devices. Magnet room RF
shielding prevents external RF energy from entering the room and degrading the MR system RF
receivers.
Electromagnetic Environment
The totality of electromagnetic phenomena existing at a given location.
Plane Wave
An electromagnetic wave which predominates in the far-field region from an antenna (or
source), and with a wave front which is essentially a flat plane.
Penetration
The passage through a partition or wall of an equipment or enclosure by a wire, cable, pipe,
waveguide, or other conductive object.
Shield
A housing, screen, or cover which substantially reduces the coupling of electric and magnetic
fields into or out of circuits or prevents the accidental contact of objects or persons with parts or
components operating at hazardous voltage levels.
SIGNA Voyager Pre-Installation
Direction 5680008–1EN, Revision 2
66
5 RF Shielded Room Requirements
