To guard against accidents and injuries to patients and other individuals as well as damage to magnetic resonance (MR) systems, the general and immediate areas associated with the scanner (also referred to as the MR environment) must have supervised and controlled access. Supervised and controlled access involves having MR safety-trained personnel present at all times during the operation of the facility to ensure that no unaccompanied or unauthorized individuals are allowed to enter the MR environment. Importantly, MR safety-trained personnel should be responsible for performing comprehensive screening of patients and other individuals before allowing them to enter the MR system room.
Additionally, it is necessary to educate and train individuals who need to enter the MR environment on a regular basis (e.g., custodial workers, transporters, security personnel, firefighters, nurses, anesthesiologists, etc.) regarding the potential hazards related to the powerful magnetic field of the MR system. Unfortunately, even with proper MR safety procedures in place, many individuals and patients have inadvertently 'wandered' unattended into the MR environment, and these situations have resulted in problematic or disastrous consequences.
As one means of helping to control access to the MR environment, the area must be clearly demarcated and labeled with prominently displayed signs to make all individuals and patients aware of the risks associated with the MR system. Access to the MR environment must also be monitored and controlled on a continuous basis.
Signs with appropriate content and information were designed to promote a safe MR environment. According to the U.S. Food and Drug Administration document entitled, Guidance for the Submission Of Premarket Notifications for Magnetic Resonance Diagnostic Devices (issued November 14, 1998), Attachment B, states: "The controlled access area should be labeled 'Danger - High Magnetic Field' at all entries." Also, this FDA document indicates, "Operators should be warned by appropriate signs about the presence of magnetic fields and their force and torque on magnetic materials, and that loose ferrous objects should be excluded."
In consideration of the above, the sign used for the MRI environment states:
Additionally, to inform everyone about the powerful static magnetic field associated with the MR system, especially individuals unacquainted with MR technology, the following information is prominently shown on this sign:
STRONG MAGNETIC FIELD
THIS MAGNET IS ALWAYS ON!
With respect to the information for implants and devices, in addition to cardiac pacemakers, implantable cardioverter defibrillators (ICDs) are also potentially hazardous for patients and individuals in the MR environment. Therefore, this information is included on the sign used for the MR environment. Notably, the peer-reviewed literature has reported that many types of metallic implants are acceptable for patients undergoing MR procedures. As such, this information is clarified on the current sign, with individuals and patients informed to consult MRI professionals if there are questions regarding this matter, as follows:
Persons with certain metallic, electronic, magnetic, or mechanically-activated implants, devices, or objects may not enter this area. Serious injury may result. Do not enter this area if you have any question regarding an implant, device, or object. Consult the MRI Technologist or Radiologist.
Finally, the sign also states:
Objects made from ferrous materials must not be taken into this area. Serious injury or property damage may result. Electronic objects such as hearing aids, cell phones, and beepers may also be damaged.
Many individuals fail to realize that the MR system's static magnetic field is always on. In fact, investigations of accidents that involved relatively large ferromagnetic objects like oxygen cylinders, chairs, IV poles, and wheelchairs revealed that the offending hospital personnel thought that the powerful magnetic field was activated only during the MR procedure. Therefore, a smaller sign or decal is particularly useful to emphasize the potentially hazardous nature of the MR environment, which states:
DANGER! THIS MAGNET IS ALWAYS ON!
Sign Placement. The strategic placement of signs in and around the MR environment is crucial to ensure that all individuals and patients see them before entering this area. In general, a sign should be placed on the door or entrance to MR system room and near or on the doorframe to be viewed by individuals and patients, especially if the door to the MR system room is open.
*To obtain the afore-mentioned signs designed to help control access to the MR environment, please visit distributors of MRI specialty products.
U. S. Department Of Health and Human Services, Center for Devices and Radiological Health Food and Drug Administration, the document entitled, Guidance for the, Submission Of Premarket Notifications for Magnetic Resonance Diagnostic Devices, Issued November 14, 1998.