The power of magnetic resonance imaging (MRI)

Magnetic resonance imaging (MRI) can be used to produce detailed cross-sectional images of the human body, enabling a precise assessment of organs and pathological changes. MRI is based on a very strong static magnetic field (typically 1.5 to 3 tesla), spatially varying magnetic field gradients, which are used for image localisation, and high-frequency alternating electromagnetic fields in the radio-frequency range, which excite the hydrogen nuclei in the body into resonance.

MRI is a safe imaging technique that operates without ionising radiation. Nevertheless, there have been accidents in the past caused by the strong static magnetic field. These incidents occurred when ferromagnetic materials, such as metallic objects or certain implants, entered the magnetic field and were moved uncontrollably by the strong attractive force.

An important aspect of MRI safety is that the magnet cannot simply be switched off, as it is based on superconducting technology and is continuously cooled. A so-called ‘quench’, in which the magnetic field is abruptly switched off, is possible, but carries risks and is only intended for use in emergencies.

Find out more in our programme about the basics of MRI safety and why certain precautions are essential. Through simple experiments, you can feel the enormous force of the static magnetic field for yourself and experience first-hand why strict safety precautions are so important in MRI.

Medical notice:

Please note that a strong, permanent magnetic field is present which cannot be switched off. For safety reasons, people with implants or metallic foreign bodies are strongly advised not to enter the magnet room.