@mayoconnectuser1

You are correct about PET utilized to detect, monitor a cancer diagnosis, but PET technology (usually PET/CT) is used beyond that....Neurology, Cardiac etc. and yes they are expensive. Cardiac MRI is also making strides as well, definitely expensive. I have worked in this field for 20 years. IMO--a bit of overkill, but everyone is different.
https://link.springer.com/article/10.1007/s11883-023-01107-0#:~:text=Results%20showed%20PET%20to%20have,PET%20as%20a%20confirmatory%20test.