i didnt look this up recently, so im going on what i recall about it.
they added some radioactive stuff to my blood. then i waited an hour while it got evenly distributed through my body. then they put me in a big detector machine.
a positron was emitted. the machine recorded on a three dimensional map where that happened. this is repeated maybe a billion times (am i even close on order of magnitude? i have no idea). because the blood is where the radioactivity is, they can create a kind of three dimensional movie of where my blood is going. blood goes places where things are happening. its fuel. so cancer is a thing that is happening. they can kind of find it this way.
now ive been fasting almost 24 hours. i hope they bring some food.