For the PET scan, a serum of radioactive glucose is injected 45 minutes prior to loading me into the machine. The idea is that cancer cells eat a lot more than normal cells, so they show brighter on the scan. I guess that different radioactive tracers can be used depending on what you're looking for, but currently, the most common use is the detection of tumors.

The nurse warned me that I should avoid small children for the rest of the day. I guess that you remain slightly radioactive till the tracer isotopes decay, which takes a day or so. After being injected, I was left to read for 45 minutes in a comfy leather recliner.

The actual scan takes about half an hour. You lie down on a big plank that rises up so that you're centered in the detector donut. Then is slides you through for a quick CT scan that is done so that they can super-impose the PET Scan results over CT imagery of you in the same position. For the PET phase of scanning, the plan moves a little bit and then pauses for about 3 minutes. There was a radio tuned to some top-40 station. I would have preferred NPR, but I didn't think to ask anyone to change it before they started scanning.