Sounds like you are in good hands. A PET scan is where they inject you with glucose (sugar) that’s tagged with fluorine-19, an element that emits positrons. You lie down between two flat “cameras” that detect positron emissions, they may slowly rotate around you. The gamma cameras do 3D imaging of the spots where the glucose is being metabolized, so if you have a tumor that is growing, it shows up as a hot spot. I think this may take an hour or so, I had a different type of scan and it took just over an hour of lying very still while these big square panels sloooowlyy turned around me.
Ask where you can get a CD of the imagery, the clinic may have an “image library”. The advantage in doing that is that you can easily get a second opinion and bring the disc along with you, and it can help focus your energies and prayers, you can bring the picture up on a computer and point to it and say, that, right there, is what I’m fighting.
I think a PET scan is what I had when I had a very “jump the gun” doctor. I had to sit motionless in a chair (I fell asleep) while they imaged me for an hour. Fortunately, it was nothing.