MRI Magnet Madness

One of the cooler medical devices invented in the last 30 years has to be the MRI machine. Introduced in 1977, it represented a huge leap forward in body imaging, allowing doctors to create greatly detailed maps -- in two or three dimensions -- of an injured knee, a shattered wrist, even a patient's brain. And while MRI scans are nearly free of side-effects, they're not completely free of dangers -- mostly because the main component of an MRI scanner is an insanely powerful magnet.

How powerful? Some estimates put the strength of MRI magnets at tens of thousands of times the strength of the Earth's magnetic field. That's why hospital staff (try to) make sure you remove all jewelry and metallic objects from your person before patients get scanned. Usually metal plates in people's heads and so on are made from surgical steel that won't respond to the MRI's magnet, but there have been cases where metal staples in people's brains have come loose, triggering aneurysms, and tiny slivers of metal in people's eyes (from a previous accident, long settled) have moved, blinding them. Pacemakers and MRI machines generally don't mix, and several deaths have resulted from their unwitting combination.

To really get a sense for how crazy strong MRI magnets are, though, we must turn to YouTube. Here's a video of what I can only imagine are some unauthorized band of yahoos fooling around after hours:

As MRI magnets have gotten more powerful over the years, magnet-related accidents have spiked. The irresponsible dodos in the video above unknowingly mimicked one of the most notorious MRI fatalities, described this way by the New York Times:

The most notorious accident was the death of 6-year-old Michael Colombini in 2001 at the Westchester Medical Center in Valhalla, N.Y. He was sedated in a scanner after a brain operation when his oxygen supply failed. An anesthesiologist ran for an oxygen tank and failed to notice that the one he found in the hall outside was made of steel. As he returned, the tank shot out of his hands, hitting Michael in the head.

There are other jaw-dropping accidents on the books, too: a police officer who's gun was sucked from his holster, slammed against the MRI machine's bore and went off, firing a round into the wall. The "sprinkler repairman whose acetylene tank was yanked inside, breaking its valve and starting a fire that razed the building." Everything from floor buffers to office chairs have gotten wedged in MRI bores, usually requiring four or more people to pry them out, as in this video:

A lot of people ask, "can't you just turn the magnet off?" The simple answer is, it's not that simple. MRI magnets are cooled by liquid helium to eliminate electrical resistance so that their magnetic fields persist indefinitely, so emergency shut-offs involve very rapid venting of the helium in gas form, which can displace oxygen rapidly and be more dangerous than simply leaving the magnet on all the time. How dangerous? Here's a clip of what happens when an MRI is improperly vented, caught by a local news crew:

Of course, as long as the technicians operating them are being safe, MRIs are safe -- all this is meant to illustrate the extreme power they harness. That said, here's a little "MRI magic" to close:

College Board Wants to Erase Thousands of Years From AP World History, and Teachers Aren't Happy

One would be forgiven for thinking that the Ides of March are upon us, because Julius Caesar is being taken out once again—this time from the Advanced Placement World History exam. The College Board in charge of the AP program is planning to remove the Roman leader, and every other historical figure who lived and died prior to 1450, from high school students’ tests, The New York Times reports.

The nonprofit board recently announced that it would revise the test, beginning in 2019, to make it more manageable for teachers and students alike. The current exam covers over 10,000 years of world history, and according to the board, “no other AP course requires such an expanse of content to be covered over a single school year.”

As an alternative, the board suggested that schools offer two separate year-long courses to cover the entirety of world history, including a Pre-AP World History and Geography class focusing on the Ancient Period (before 600 BCE) up through the Postclassical Period (ending around 1450). However, as Politico points out, a pre-course for which the College Board would charge a fee "isn’t likely to be picked up by cash-strapped public schools," and high school students wouldn't be as inclined to take the pre-AP course since there would be no exam or college credit for it.

Many teachers and historians are pushing back against the proposed changes and asking the board to leave the course untouched. Much of the controversy surrounds the 1450 start date and the fact that no pre-colonial history would be tested.

“They couldn’t have picked a more Eurocentric date,” Merry E. Wiesner-Hanks, who previously helped develop AP History exams and courses, told The New York Times. “If you start in 1450, the first thing you’ll talk about in terms of Africa is the slave trade. The first thing you’ll talk about in terms of the Americas is people dying from smallpox and other things. It’s not a start date that encourages looking at the agency and creativity of people outside Europe.”

A group of teachers who attended an AP open forum in Salt Lake City also protested the changes. One Michigan educator, Tyler George, told Politico, “Students need to understand that there was a beautiful, vast, and engaging world before Europeans ‘discovered’ it.”

The board is now reportedly reconsidering its decision and may push the start date of the course back some several hundred years. Their decision will be announced in July.

[h/t The New York Times]

North America: East or West Coast?


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