In MRI zones, which zone sign is indicative of caution?

Zone 3 is indicative of caution in MRI zones. Within the MRI environment, the zones are defined according to the level of access and magnetic field strength. Zone 1 is the area where the general public can freely enter, typically outside the MRI facility, while Zone 2 serves as a buffer zone where patients and visitors can wait, still under some level of supervision.

Zone 3 marks the area directly adjacent to the magnet room, where the magnetic field becomes significant. This zone requires individuals to be under specific supervision to prevent accidental entry for those who may have contraindications to MRI, such as implanted medical devices or ferromagnetic objects that can pose a safety hazard.

It's crucial for staff to monitor this area closely and ensure that anyone entering is informed of the potential risks and limitations, thus emphasizing the need for caution in Zone 3. This clear delineation of zones helps maintain a safe environment within the MRI facility, especially as one approaches higher magnetic field strengths found in Zone 4, which is the magnet room itself.