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Magnetic Fields

Magnetic Fields

My Story as an MRI Tech Intern

By Natalie Van Sistine

I was only eighteen and entering my second year of college when I was accepted as an intern with a local manufacturing plant that built and repaired MRI machines. I don't think there was a lot that could have prepared me for that experience. I didn't grow up around big machines and my initial few weeks at the plant were filled with a steady mix of amazement and complete terror at how powerful the magnets and their systems actually were.

My primary duties during the internship were to bring magnets up to field, particularly those fresh off the assembly line. They were typically coming out of cool-down, where they were filled with liquid helium over the course of several weeks until they could safely sit at near absolute zero temperatures. To stay cool, every magnet had its own little tag-along compressor that chirped at regular intervals. All together, they made the whole plant sound like it was full of birds nesting in the rafters.

When a magnet was prepped to ramp to its field, there were also giant, two foot long leads that needed to be gradually inserted and removed from the magnet. These leads would add current steadily until the magnet had enough to sustain itself in virtually loss-less conditions. However, if the room temperature leads slid in too fast, it would be enough to warm the super freezing inner conditions of the magnet and cause a "quench." Quenches would release the liquid helium out of an emergency valve and into the test room, instantly converting from gas to solid upon exposure to the air. It would cover everything in an inch of fine snow that cost as much as my college tuition.

Of course, there is only so much you can do to describe what working with giant magnets are like before experiencing it for yourself. I found that climbing around outside of the magnets, the fields were hardly noticeable. I worked primarily on 1.5 Tesla magnets and occasionally interacted with the monstrous 3Ts in the back. All our tools were made of alloys to prevent magnetic attraction and my boots were titanium toed. The only time you were inside the magnet was older models of the 1.5Ts, where you had to climb inside of the bore and tape strips of steel in varying thicknesses around the core. This would encourage the magnetic field into a homogeneous state for the clearest image possible when fully assembled (a process called shimming) However, as the only girl on my shift, no one thought to mention that your bra's underwire is completely fair game to superconductive groping.

At 5'4", I had the rare ability to crawl completely into the magnet and sit happily cross legged, shimming to my heart's content. But my first time doing so, I made the mistake of spinning around inside of the bore too quickly. I woke up several minutes later, exceptionally dizzy and on my back, due to the strength of the magnetic field and my body's lack of conditioning to it. When I sat up, my bra immediately flipped up at an awkward angle beneath my shirt. It startled me so much that I started laughing hysterically and scared the other technician standing nearby.

Other than the occasional unidentified flying pen, I didn't have too much trouble with the standard 1.5Ts. However, my coworkers told the occasional outrageous story of things like chairs getting sucked into a bore when left too close. Apparently, it takes three grown men to pull something that big back out. The magnets were also highly susceptible to barometric changes, especially when establishing their initial field after their first ramp, and an ill-timed cold front could ruin weeks, worth of tests. As a result, there was never a shortage of bizarre stories from week to week.

If you have an electronics story you'd like to share, please send it to [email protected].
Natalie Van Sistine is a professional writer, voice actress, and sound designer based out of South Carolina. After growing up listening to audio books and radio drama, she decided to pursue her interest in sound and writing at Columbia College Chicago.