Mrs Blogger and our 9yr-old son will be driving me to my 2 PM's PET scan. I hope he will find it home-school educational.
Once you get past the atomic physics of it PET scans are kind of the simplest scans to understand:
1) My body is made "restful", neither eating anything in the last 18 hours that would spike glucose (fats and protiens only; no sugars/starches), nor any strenuous exercise in the last 48 hours that would deplete stored glycogen, muscle's "local supply" of glucose.
2) I will be injected with a glucose molecule with a radioactive tag
3) The tagged glucose will be drawn to places that are "busy" despite my restful state (as I lie on a table)
4) As the radioactive glucose sends out radiation* that says "Glucose was here" a big donut gamma-ray detector pinpoints where it is coming from as I'm threaded in and out of the donut.
5) The constructed picture shows glucose hot spots. The brain and liver are usually hot, but it is the "elswhere" hot spots that are telling. This person (SAMPLE, NOT ME) has was looks like lymphoma in their shoulders, gut and groin:
* The part that is not easiest to understand but is still super cool: Fluoride 18 loses a positron (a bit of antimatter with the mass of an electron, but with proton's +1 charge), which quickly smashes into an electron and they cancel their charges to zero and their masses muturally-annihilate into a puff of two gamma rays. The gamma rays pass out of me to be detected. The Flouride 18 (made fresh today, given a half life of just 109 minutes), turns into harmless, stable (but rare) Oxygen 18 (which you might call "heavy oxygen")
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