How Magnets are used within MRI machines

Author: Christopher Peters, Magnetics Expertย  ย  |ย  ย  Date: 9th March 2019

When we think about magnets and where we may find them being used around us, many of us forget about the world of medicine. A little known fact is that magnets are used within MRI machines with the help of radio waves to take a deep look into your body and help diagnose illnesses.


What is an MRI Scan / Machine

The clue is within the name MRI is short for Magnetic Resonance Imaging, this takes a deeper look into your body than other methods such as an x-ray diving in to much more detail. With an MRI scan you are able to see joints, muscles, tendons ligaments and much more. As you can imagine this allows conditions to be diagnosed quicker and easier. Conditions such as tumours, spinal injuries, strokes and joint injuries which would of usually require multiple tests and at times guesswork are much more scientific.


How does this work?

MRI machines use strong magnetic fields to align the protons which are in the water molecules of your body. The human body is largely made from water molecules and a water molecule contains a hydrogen nuclei with a single proton. The clever part is when water molecules are placed within a magnetic field the protons become aligned and point in the same direction.

Next the MRI machine will send a quick burst of radio waves at the water molecules, this disrupts the magnetic field. While the magnetic field is disrupted the protons move out of alignment and then when the radio wave stops the protons move back into alignment.

When the protons move back into alignment they send out a signal and it is this signal which is picked up by the MRI machine. Through this process the MRI machine builds a picture, and within this picture you are able to distinguish between different tissues.

So there you have it that is how magnets are used within an MRI machine and why we should all appreciate just what magnets can do. Next time you have an MRI scan just think about the amazing innovative technology which is taking place.