MRI scanner rooms are RF shielded both to protect that which is outside the room from the RF energy produced by the scanner and to prevent electromagnetic signals from the external environment interfering with MR signal detection. The RF shield is a layer of thin copper or aluminum sheet. The doors and windows are an integral part of this lining and so the door must be closed during scanning. Monitoring cables and medical gas supplies which pass into the shielded room must be made of non-conducting materials and travel through dedicated waveguides so the shield is not breached. This includes gas and drug delivery pipes. Cables that carry power or signals must be fibreoptic or pass through low-pass electrical filters. A number of professional bodies, such as The Association of Anaesthetists of Great Britain and Ireland (AAGBI), recommends that all monitoring devices are placed in the control room outside the MR scan room. Table 13.2 provides a list of common problems that need to be considered by the intensive care team in the MRI scanner.