Scanners Set for...What Exactly?

So time passes and I'm eventually escorted to the room where the scanner resides. I get signed in, sign some waiver forms acknowledging all the terrible (but unlikely) things that might happen, and the technician explains the process. I'm to climb on the cot, lay flat on my back and try not to move.* The cot will slide into the machine and a couple of light up icons at the top of the ring will tell me to inhale, pause and hold my breath, and then exhale slowly. The cot will pass slowly through the ring and take its pictures. Lather, rinse, repeat.

Things get interesting when he tells me about the contrast agent. The contrast agent will be administered through the IV that had been placed earlier in the morning. The tech tells me "nine out of ten" people experience a feeling of cold water running down their back, and almost as many report feeling like they're wetting the bed. He assures me, however, that in the twenty-plus years he's been doing this he's never seen anyone actually wet themselves. Good to know.

And so we begin.

I get on the cot and do my best to get comfortable. After a couple of minutes the tech lets me know that he's going to administer the contrast agent. A minute passes and I start thinking, "Hey, I'm one of the few that don't feel cold water." Then another passes and the thought changes. "Nope, I'm one of the nine." And yup, it totally feels like I'm wetting the bed. Weird sensations aside, I remain still, the scan proceeds, and eventually to cot comes to a stop outside the machine. Through the intercom the tech tells me to wait without moving so he can set up some check scans. 

That is so not going to happen.

By this time, I've been flat on my back for at least ten minutes and my back has had enough. I hold out as long as I can, but in this case "as long as I can" is about twenty seconds. Soon I'm up on my elbows and the pain is draining from my back. But that's apparently enough to end the scanning process. I've moved, so there won't be any check scans.

It's back to treatment room to wait for the results. 

* A little bit of context regarding my back. Like many tall individuals, I'm prone to low back pain. And in recent months, the pain's been as bad as I can remember it ever being. I've bought two mattresses in the last eight weeks in an effort to be able to sleep through the night, and at my last dental cleaning I had to ask the hygienist to clean my teeth while I was sitting up. These days, a few minutes on my back and I'm in agony.