Enoch’s Thoughts

August 23, 2010

Pets, antimatter, and the Beatles

Filed under: Uncategorized — etblog @ 10:12 am

In the late 70s, a non-invasive diagnostic device was introduced into medical practice. It was originally called the Computed Axial Tomography (CAT) scanner, which unavoidably led me to a terrible pun which doesn’t really translate to writing. (That small technicality is not enough to prevent me from proceeding, much to your lack of surprise, I’m sure.) I would say, “Did you know that dogs can’t see through people, but cats can.” CATscan. Get it?

I finished the short book in Antimatter last week. I confess, antimatter sounds like something that was made up by a clever science fiction writer. Antimatter is made of antiparticles with polarities, charges, and spins exactly the opposite of those that make up our world. Its great plot value is that, if antimatter should ever come in contact with “ordinary” matter, the result would be a complete conversion to pure energy, probably involving a giant explosion, which would leave no trace of the original matter.

Antiparticles were originally postulated by physicist Paul A. M. Dirac in 1928 to explain a theoretical physics conundrum. Other scientists proposed that antimatter was created at the same time as matter in the big bang, and in equal quantities. While this solves some problems, it creates others, such as, “Where is all that antimatter now?”

Antimatter and antiparticles would have been an arcane and little-known theory, until still other scientists began to find actual evidence of antiparticles in their cloud chambers and bubble chambers. With careful observation, experimental physicists can now consistently detect the occasional appearance of antimatter particles on earth. It seems that antimatter particles are created in small but measurable quantities when cosmic rays strike the molecules in our atmosphere.

Finally, high-energy physicists (you know, the ones that drink a lot of Red Bull) succeeded in actually generating positrons (the antiparticle equivalent to the common electron), and figuring out a way to store significant numbers of positrons in an electromagnetic field. (Obviously you can’t just put them in a bottle. It’s much like the joke about the guy who invented the universal solvent, but couldn’t find anything to keep it in.)

All of this would have remained trapped in the mind-numbing realm of physics journals and graduate-level textbooks if a series of clever scientific medical technologists hadn’t figured out how to actually use positrons for medical diagnosis.

Editorial note: I realize that the preceding paragraphs are full of passive voice and vague descriptions such as “scientific medical technologists.” If you haven’t figured it out yet, scientific discovery is a messy process, frequently involving scores of contributors over decades. Rather than omit critical participants, or boring you with long lists of names, I’ve decided to summarize in this rather crude fashion, and leave further study as an exercise for the reader.

Anyway, it turns out my pun about dogs was at least partly wrong. Apparently feral animals can’t see through people, but pets can. Yes indeed, Positron Emission Tomography (PET) scanners are based on the use of positron antiparticles, which are actually generated by small cyclotrons and embedded into tracer fluid that is injected into the patient. The positrons eventually collide with electrons, their matter-based counterparts, and each collision generates two gamma rays that fly directly apart from each other. Detectors positioned around the body part of interest use these gamma ray emissions to track and record biological activity in the area.

I find this to be an amazing story. Dirac modestly proposes a purely theoretical solution to a quantum physics problem, and over the next five decades, his theory is not only confirmed, but turned into a rather clever medical diagnostic tool. This ranks right up there with my previously-posted infatuation with the laser.

And the Beatles? It turns out that much of the development work leading to the CT Scanner was done by EMI, an electronics research company now better known for their music and recording prowess. Their recordings of a then-obscure British pub band produced unexpected commercial success, helping fund their development of medical products, including the CT scanner.

So, in response to all those well-intentioned adults in the 60s who thought Beatles fans should have their heads examined, they can now have them examined more quickly and conveniently thanks to, er, the Beatles.

1 Comment »

  1. […] for today I present two pet scans (not related to the CATscan joke I made in a previous post) for your mild […]

    Pingback by Petoons « Enoch’s Thoughts — February 5, 2011 @ 12:28 pm

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