Thursday, after some delays I don’t fully understand, I spent an afternoon in the realm of science fiction. I was given a dose of a chemical from a heavily-shielded syringe, then put in the Radioactive Person Quiet Room for an hour, then my body was passed three times through the hole in a large, whispering machine.

The technology is amazing, and I will enjoy telling you about that. The experience of the technology is a bobsled ride down into your own head. I will tell you about that too, but it won’t be as fun.

As I describe the procedure to people, I get excited. The procedure is pretty amazing; the stuff of science fiction only two decades ago. Starting with the question “how can we detect where cancer cells are inside someone without cutting them open?” you quickly get to a place that has been a long time coming.

Medicine, you see, for the last century or so, has actually become a science. Cancer is now treated by the medical equivalent of engineers. Big Physics had its day, with massive particle accelerators and whatnot, but the priority has changed to using what Big Physics yielded to improve lives directly.

Take antimatter, for instance. Here’s the sequence of steps that led to PET scans:

1. We need to find concentrations of cancerous cells.
2. Cancerous cells are in overdrive, and consume lots of energy.
3. If we can find cells consuming abnormal amounts of energy, we can find the cancer.
4. Hungry cells demand lots of energetic molecules like glucose.
5. Follow the money: if we can trace where the glucose is going, we can find the hungry cells. But how do we track the glucose?
6. We can detect the source of gamma radiation very well, right through any intervening tissue. So if we had gamma-emitting glucose, we could follow it around.
7. Hello, Fluorine-18. It is an unstable isotope, but its magic is that when it decays, it emits a positron. Antimatter! That positron won’t get far before it runs into an ordinary electron, and sure as you can say e = mc², the m of the two particles becomes e, a gamma photon that can be detected.

After I waited for the tracer to make its way through my body, I was called into the Chamber of the Magic Donut. It is a room that is terribly ordinary — linoleum floor, fluorescent lights, standard drop ceiling — a surprisingly drab setting for the machine that filled the middle of the room. The machine itself, I didn’t stop to inspect when I got there. I had other thnings on my mind.

I thought perhaps there would be a bin where I could put my metallic belongings, but instead the Guardian gestured to a chair. “You can leave your stuff there.” I was a little bothered by the informality of it, but I put my stuff on the chair. I guess I was expecting something more planned – people will need a place to put their belongings. Or perhaps I was expecting something entirely more ceremonial.

I had been told to dress warmly, so I had worn sandals so I could put on winter socks when the time came.

“Don’t take off your shoes,” the very nice man said. He was large, and a little hunched over, and reminded me of a mythical creature tasked with guarding the sanctity of the chamber. “Your sweat is radioactive, and if you get it on the floor it could throw off the measurements.” It was not as cold in there as I had been led to believe, so I forwent the socks, and climbed up onto the Great Tongue Depressor – the platform that would pass me though the Hole of the Magic Donut.

So, loaded with ¹⁸L I lay down and allowed the Guardian of the Bridge to strap my hands to my side. I took a breath and closed my eyes.

The first two passes were quick; the first was just so the machines could measure my position. The second was a CT scan. Pf. That science fiction is old news now. Both those scans were over in a couple of minutes. Then came the PET.

It started from my thighs and worked its way up. By now many people had reminded me that it was important to hold still. So I did.

Another fun fact you might not know about me is that I have a skin condition on my face that can get itchy. It was only a matter of minutes before an itch on my face, unscratched, grew into something else. Like something was hollowing out a part of my cheek and replacing it with an ache designed purely to annoy.

But I held still, and every few minutes I would be moved a few inches. It was impossible not to think about where I was inside the donut and what the data it was gathering at that moment might mean. My pelvis, where there is certainly cancer – but has it reached bone? Then the gut, then the thorax (does my breathing make those images less reliable?) and finally the brain.

Shit. Please not the brain.

Each time the Tongue Depressor moved me within the Magic Donut, I had nothing better to do than imagine what it was seeing at that moment, and what that might mean. Imagination is a curse, sometimes.

There were at least two people in the control room; they probably shared knowing glances as the scan came to life in front of them, deciding when the image was good enough to move to the next slice.

But that was Thursday, and the weekend arrived before the radiologist could sign an assessment, so I have been waiting, less or less patiently. Tomorrow I hope I will learn the results, and see what the next phase of Science Fiction holds in store for me.