What is the primary action advised for pregnant MRI staff during active scanning?

The recommended guidance for pregnant MRI staff during active scanning is to avoid remaining in Zone IV. Zone IV is the area that encompasses the MRI room where the magnetic field is the strongest, and it is here that exposure levels might raise concerns due to prolonged proximity to the MRI system. Since the potential risks of exposure to the RF fields and static magnetic fields in this high-field area during an active scan are not entirely understood, pregnancy raises additional considerations regarding safety.

Hence, avoiding Zone IV minimizes any risk to both the staff and the developing fetus. It's a precautionary approach to ensure the safety of pregnant personnel while still allowing them to contribute to patient care in safer areas, such as Zones I, II, or III, where the magnetic field's influence is much less significant.

The other options, such as operating the MRI machine or wearing lead aprons, do not adequately address the unique safety concerns associated with being pregnant in active scanning settings. Lead aprons provide some protection against ionizing radiation, but they do not mitigate the specific risks presented by the magnetic fields in the MRI environment.