At 1:40 it is stated that PET scans require a contrast agent. I believe the correct term is radiopharmaceuticals, which emit radioactivity. Contrast media in fact do the opposite- they absorb radioactivity- making the anatomical image clearer.
I don't get how the detector can know the location of the Annihilation when both 180° y-rays are detected at the same time. Does the detector compare the amplitude of the Photon energy? It must compare something to know the difference in distance of the travel from the 2 y-rays right?
I'm not in the med field, never been to college, but I've read enough stuff on quantum physics to understand this, and being I have gotten some nuclear med tests and will prob get more it's always good to have an increased grasp of how it all works. and when there's 4 of you w radioactive stuff in your veins you can make jokes about being 'hot ppl', there's always some staff that doesn't think it's funny but most do and your fellow patients usually find it amusing, reduces the stress of the tests, especially if you're doing a cardio stress test. PET scans you get to make jokes about antimatter in your body. Astrophysics is another interest of mine, big physics, small physics and reg physics, the more you understand the bigger your world is, and my world is huge, but for every door you open to learn more, there's always 10 more doors. Like they would say in metaphysics, 'become one w the doors and the documentaries'. I've been watching docus all my life, I was born in 63, yrs worth of docus. Tv ones aren't so great anymore but plenty on YT !