Why is copper foil used for MRI shielding and how does it work?

Magnetic resonance imaging, commonly referred to as MRI, is a non-invasive diagnostic imaging technique widely used by healthcare professionals to visualize internal body structures.  MRI uses strong magnetic fields and radio waves to create detailed images of the body’s organs, tissues, and bones.

 Regarding the MRI machine, a question that often arises in people’s minds is why the MRI room should be copper-plated? The answer to this question lies in the principles of electromagnetism.

 When an MRI machine is turned on, it generates a powerful magnetic field that can affect nearby electronic devices and systems. The presence of magnetic fields can interfere with other electronic equipment such as computers, phones, and medical equipment, and can even affect the performance of pacemakers.

To protect these devices and maintain the integrity of the imaging equipment, the MRI chamber is lined with copper foil, which acts as a barrier to the magnetic field. Copper is highly conductive, which means it absorbs and disperses electrical energy and is effective at reflecting or shielding magnetic fields.

A copper lining along with insulating foam and plywood forms a Faraday cage around the MRI machine. A Faraday cage is an enclosure designed to block electromagnetic fields and prevent interference with electronic equipment.  The Cage works by distributing an electrical charge evenly across the surface of the cage, effectively neutralizing any external electromagnetic fields.

Copper foil is not only used for shielding, but also for grounding.  MRI machines require high currents to be passed through the coils that generate the magnetic field. These currents can cause a buildup of static electricity that can damage equipment and even be dangerous to patients. Copper foil is placed on the walls and floor of the MRI chamber to provide a path for this charge to safely discharge to ground.

In addition, using copper as a shielding material offers several advantages over traditional shielding methods. Unlike lead, copper is highly malleable and can be easily fabricated into various shapes and sizes to meet the specific requirements of an MRI room. It is also more cost-effective and environmentally friendly than lead.

In conclusion, MRI rooms are lined with copper foil for good reason. The shielding properties of copper foil protect imaging equipment from external electromagnetic interference while ensuring patient and staff safety. The copper foil is combined with other materials to form a Faraday cage that contains the magnetic field generated by the MRI machine in a safe and controlled manner. Copper is an excellent conductor of electricity, and using copper foil ensures that the MRI machine is properly grounded. As a result, the use of copper foil in MRI shielding has become standard practice throughout the medical industry, and for good reason.

Post time: May-05-2023