**3.2. MRI suite design and zones**

An MRI suite should be designed to restrict access and limit exposure to static magnetic fields. Various publications have provided different designs to the MRI suite to ensure max‐ imum safety and they all showed that an MRI suite should be built to restrict access by zones (Gould 2008; Kanal *et al.,* 2007; Junk and Gilk, 2005; Shellock and Crues, 2004). The zones suggested by the various articles are as follows;

is the need to use MRI- safe equipments to address the situation with restrictions of public first responders from zone IV of the MRI environment until safe conditions are established or responders are verified to be safe (Junk and Gilk, 2005). Access to zone IV should be ena‐ bled by a programmed key and the key kept in a restricted access box in the MRI control

Assessment of Safety Standards of Magnetic Resonance Imaging at the Korle Bu Teaching Hospital…

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Architectural and design engineering for a MRI suite have been established in standards published by the Joint Commission on the Accreditation of Health Organisations (JCAHO), the American College of Radiology guidelines, the International Building Code (IBC) and

Shellock and Crues (2004) emphasized that the establishment of thorough and effective screening procedures for patients and other individuals is one of the most critical compo‐ nents of a programme to guard the safety of all those preparing to undergo MR proce‐ dures or to enter the MR environment. All preliminary patient history, MRI safety screening and documentation must be completed and signed by the patient, guardian or clinician before procedures are undertaken on patients (Shellock and Crues, 2004; Ferris *et al.,* 2007). Various screening forms are used for different categories of people who come to the MRI suite. In general, screening forms are developed with patients in mind (Sawyer-

Various means have been adopted to help with ensuring safety in an MRI unit. This is usu‐ ally meant to provide on the spot recognition of MR- safe equipment and surroundings, likewise unsafe and MRI-conditional equipments and locations. At the University of Califor‐ nia San Francisco (2011), yellow is used to signify caution and is painted around the en‐ trance of the door. Gas tanks that have been painted green signifies ferrous cylinder and hence make it easy for identification as MRI unsafe equipment. For safe MRI tanks, the cyl‐ inders are coloured silver. Symbols have also been used as a new classification system for

An MRI safe symbol signifies that the device or implant is completely non-magnetic, nonelectrically conductive, and non-RF reactive, eliminating all of the primary potential threats during an MRI procedure. An MRI Conditional sign is used to identify a device or implant that may contain magnetic, electrically conductive or RF-reactive components that is safe for operations in proximity to the MRI, provided the conditions for safe operation are defined and observed (such as 'tested safe to 1.5 teslas' or 'safe in magnetic fields below 500 gauss in strength). Finally, an MRI unsafe symbol is reserved for objects that are significantly ferro‐ magnetic and pose a clear and direct threat to persons and equipment within the magnet room. An appropriate coding system is thus necessary to be adopted by every MRI unit to

Occupational Safety and Health Administration (OSHA).

**3.3. Pre- screening and screening forms**

Glover and Shellock, 2002).

**3.4. Colour and symbol coding**

implants and ancillary clinical devices.

facilitate easy identification of safe items.

room.

Zone I: - Opens to the general public and presents the least exposure to the patients, staff and visitors. Usually it is the reception and waiting room for the MRI suite purposed to channel patients and medical staff to the pre-screening area (zone II) and limit entry to the MRI suite.

Zone II: - This is the first interaction site for patients, visitors and staff in the MRI suite. The purpose of this zone is to restrict further public access to the suite and provide direct super‐ vision of patients and visitors by the MRI staff. Pre-screening of all patients, staff and visi‐ tors also takes place here. If ambulatory, the patient is screened through a ferrous metal detector installed into the zone II. Non ambulatory patients in walkers, wheelchairs or pa‐ tient support need the transport equipment to be verified as MRI- safe or exchanged for MRI- safe equipment. The zone II generally has a metal detector and a 1000 gauss magnet to help screen medical equipment for ambulatory patients. MRI staff including the MRI tech‐ nologist is directly responsible for enforcing strict adherence to the MRI safety protocols for the MRI suite and patient safety.

Zone III: - This is the entry zone to the MRI machine room which is zone IV. Entrance to this zone is restricted physically and by protocol. Being the last barrier against an incident or in‐ jury due to an interaction of a static or active magnetic field and any unscreened personnel, patient or equipment, only MRI technologist, certified staff and pre-screening attending physician accompany the patient into the MRI machine room. The portal or entrance to the MRI machine room must be monitored by a second ferromagnetic- sensitive detector and door must be locked. Sounding of detector will require verification of either an MRI- safe or compatible event or the discovery of an MRI–unsafe condition in the patient, transporting or medical equipment or the attending medical staff. The standard access method is a card ac‐ cess system which should allow access to only certified MRI staff between zone III and zone IV. All medical staff must be pre-screened prior to entry into zone III to make sure no unscreened individuals will be allowed access to zone IV. Ideally, the personnel in zone III must be uniformed in MRI compatible scrubs which will avoid the use of identification badges in the suite, MRI-safe shoes and undergarments. Personnel must avoid all jewellery, watches metallic writing instruments, and wire-framed glass which may raise a false alarm from the detector (Shellock and Crues, 2004).

Finally in zone IV, the MRI room should have a clear demarcation of the five gauss line tap‐ ed or painted on the MRI suite floor to indicate the area beyond which requires MRI- safe or MRI – conditional equipment or instrumentation. This should be in line with the distance and tesla rating of the MRI. Zone IV should be clearly marked with a red light and lighted sign stating, "The Magnet is on." In situations where an alarm goes off for a code red, there is the need to use MRI- safe equipments to address the situation with restrictions of public first responders from zone IV of the MRI environment until safe conditions are established or responders are verified to be safe (Junk and Gilk, 2005). Access to zone IV should be ena‐ bled by a programmed key and the key kept in a restricted access box in the MRI control room.

Architectural and design engineering for a MRI suite have been established in standards published by the Joint Commission on the Accreditation of Health Organisations (JCAHO), the American College of Radiology guidelines, the International Building Code (IBC) and Occupational Safety and Health Administration (OSHA).
