The purists can argue about steel vs. aluminum roller coasters all they want. For my insurance company’s money, the MRI is the only way to ride.

After getting my hand strapped into a coil with a thick cable curling off it, I was lifted into the giant tube for what the tech kept calling ‘the money shot’. As I approached, I learned that 1.5 MTeslas of magnet can pull a forgotten nickel out of your back pocket fast enough to hurt.

That was the last of the excitement, though. Once the tech spent a minute wrestling the nickel from the side of the machine where it hung, the experience was similar to the one any of us have had who have been tranquilized in an uncomfortable position and forced to listen to German techno for 45 minutes at volume. The machine fires up with a calibration sequence, left then right then both with a rising center, like THX at the movie theatre. Then it begins uttering squeals as zips up and down frequency ranges, trying to isolate fat, then veinous tissue, then blood, on and on, shifting into a more pure harmonic every five minutes or so to recalibrate.

All the while, the table on which the patient lies is shifting, sometimes more, sometimes less: the most precise images are derived when the bursts are directed directly into the isocenter of the magnet. These magnets can be electrically tuned to some degree to ‘look’ off the center, but the bore is by nature cylindrical and the image is not as precise away from this sweet spot. The reason for this is the same as the reason image on a television doesn’t line up quite as well in the corners: the gun in your television prefers to make circles. Very strong magnets can wrestle the image into something approximating a rectangle, but there are limits. This is why until recently TV screens weren’t perfectly flat, instead curving around to make the job of the magnets easier.

In the mean time, all you have to do is lie very, very, very still. Don’t think about your nose itching, first off. And your arm certainly isn’t falling asleep; don’t think about it, about quicksilver numbness seeping into one thumb, your elbow humming slightly… .