What Should I Know About MRI Safety?

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  • Written By: Alex Paul
  • Edited By: R. Halprin
  • Last Modified Date: 05 July 2019
  • Copyright Protected:
    Conjecture Corporation
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In most cases, an MRI is a secure and reliable form of medical testing. MRI safety is still important, however, as the strong magnetic fields can cause potential problems. Any magnetic object in the room, for example, may rapidly move towards the machine when it is turned on and can cause injury. If the patient has any magnetic objects in his or her body, such as certain types of pump or implants, this can also be dangerous. Other potential safety issues include hyperthermia caused by heating from the radio transmitter and discomfort caused by claustrophobia.

An MRI scan uses strong magnetic fields to form an image of the body’s tissues. This strong magnetic field will attract anything that is ferromagnetic, often at high velocities. If a projectile hits a patient during an MRI scan, this can result in serious injury. There are even recorded deaths from this type of accident. For this reason, it is essential to maintain MRI safety by ensuring that the patient is wearing nothing metallic, such as watches or necklaces.

If the patient has any device inside his or her body, such as a pacemaker, this makes MRI safety more difficult. In some cases, special protocols need to be followed to ensure that the scan can take place safely. Sometimes, the scan may have to be canceled completely. Some examples of implants which cannot be present during an MRI scan include insulin pumps and nerve stimulators.


Inside the MRI machine is a radio transmitter which is used to obtain a clear image. In some rare cases, this can cause heating in the patient’s body and even lead to hyperthermia. This type of MRI safety issue is most commonly encountered in overweight patients.

The confined space of an MRI machine may also cause potential safety issues. For MRI scans of the lower limbs, the patient is not always required to be enclosed. There are a number of situations, however, where the patient must lie in a small space for a long period of time, which can lead to feelings of claustrophobia.

There are numerous other potential MRI safety issues, but most are extremely uncommon. The vast majority of problems can be avoided if the technician is given full and accurate information by the patient and the referring doctor. There has, however, been a recent increase in MRI safety problems occurring in U.S. imaging facilities, although the reason for this has not yet been established.



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Post 1

RE: magnetic objects moving toward the machine.

Virtually all contemporary MRI scanners have 'always on' magnetic fields. This is either because they are permanent magnets (really big versions of what's stuck to my fridge door right now) or, more commonly, superconducting magnets. The latter can be turned off, but this requires special equipment and specifically trained personnel to do it ($$).

There are systems of the MRI which are only turned on when imaging a patient, but those systems aren't the main, super-powerful magnetic field.

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