MRI Room Construction: Ensuring Safety and Image Quality

Guidelines for Structural Metals in MRI Rooms

MRI rooms are specially designed to accommodate the powerful magnetic field generated by the MRI machine. To ensure safety and maintain image quality, MRI manufacturers have strict guidelines regarding the proximity of structural metals to the isocenter of the magnet.

In a 3 tesla MRI exam room, steel rebar cannot be used within approximately 6 feet of the isocenter. Instead, fiberglass rebar is employed in a 12" thick concrete slab. This substitution prevents blurriness in the MRI images caused by the presence of magnetizable metal.

Proximity of Ceiling and Walls to the Isocenter

The guidelines also extend to the ceiling of the MRI room, which needs to be kept within 6 feet of the isocenter. To meet this requirement, an aluminum ceiling grid is used. Additionally, the wall inside the radio frequency (RF) shielding is made of normal metal studs, but anything inside the RF shielding must be made of non-magnetic materials such as stainless steel.

Magnetic Shielding and Floor Protection

Beyond the specified distance from the isocenter, the MRI machine cannot exert enough force to damage the floor or pull the rebar. Concrete, reinforced with fiberglass or epoxy, is strong enough to resist being pulled by the MRI machine, eliminating concerns about rebar being pulled through the concrete.

Magnetic shielding is typically only employed when there is sensitive electronic equipment in an adjacent room that could be affected by the MRI. The RF shielding in the MRI room, on the other hand, is primarily designed to prevent radio waves from entering the room, not to affect the magnet's strength.

Construction Materials and Image Quality

MRI rooms require walls and hardware made of copper, aluminum, or other non-magnetic alloys to prevent interference with the MRI machine. The floors in MRI rooms have an extra layer of cement paneling on top to further protect the structure from the effects of the MRI.

The strength of the magnetic field decreases by the square of the distance from the magnet. Combined with the specially built MRI rooms, the distance between the MRI and the concrete wall/floor is sufficient to reduce the magnetic forces to normal stresses, ensuring the safety of the structure.

Conclusion

MRI rooms are not ordinary rooms; they require specific construction and materials to ensure the proper functioning of the MRI machine and maintain the quality of the MRI images. The guidelines and specifications for MRI room construction play a vital role in guaranteeing safety, preventing interference, and providing accurate and clear images. By adhering to these guidelines, MRI facilities can ensure optimal performance and patient care in their diagnostic imaging processes.