What should you know about an MRI scanner magnet?

The magnet surrounds the opening of the scanner and produces the field that makes MRI possible. Radio waves briefly disturb signals from hydrogen in body tissues; the system detects their return and uses that information to build images. The magnet itself does not take a picture like a camera, but it provides the physical conditions needed for the scanner's coils and computer to do so.

The field is present even when no examination is running. Ferromagnetic objects can be pulled toward the scanner, while some implants or devices may heat, move or malfunction. Some implants are MRI-conditional, meaning scanning is allowed only under specified conditions. The imaging team must verify the exact device and its safety information.

Tell the team about pacemakers, implanted pumps, clips, stimulators, metal fragments, hearing devices, tattoos with metallic pigment and previous surgery. Remove jewellery, watches, cards, keys, phones and clothing with metal fasteners as instructed. Do not take an object into the scan room unless staff have checked it. If you feel anxious in the narrow space, mention this when booking so suitable support can be discussed.

The [MRI Scanner](/technology/mri-scanner/) page gives an overview of the equipment. A clinical [MRI Scan](/treatments/diagnostics-and-staging/mri-scan/) may use different coils or contrast depending on the body area and the question being investigated.

Contact the imaging service promptly if you remember an implant, metal fragment or device after completing the safety form. During a scan, report heating, pain, unusual pulling, dizziness, distress or any new sensation immediately using the call button. For sudden neurological symptoms, severe breathing trouble, chest pain or a major injury, seek urgent medical help rather than waiting for a routine MRI appointment.

Is my implant safe for this scanner and under which conditions? Will the examination require contrast? Can I have support if I am claustrophobic? What should I do with medication patches, glucose sensors or other wearable devices?