Someone correct me if I am wrong, the pet and ct scan are done together. The ct scan is used to show where the uptake is. I noticed that sharlee wrote that they said they couldn't do them both on the same day. I have had all three done in the same machine one right after the other. I would check into this sharlee, one of the things that has caused me prob is not having all the info from the first pet scan to compare with the last two. Unfortunately it doesn't exist but it would have been very helpful. The pet scan shows the uptake but is not the best for showing the exact location, when done with ct it is very accurate at both pre treatment. After treatment it gets a little more difficult. Good luck with all of your mom's treatments Donna.