No scan is 100% accurate, but the PET/CT is pretty high in the 90% range. It also depends on the area looked at, and what for, so the CT, MRI, may be superior looking at bone, soft tissue, nerve, veins, others, but the PET/CT is "generally" superior, followed by the MRI high 80 range and then CT mid 70%. The CT is most often used, is the cheapest, and needs no specialized training like a PET/CT. The PET/CT can detect cancers as small as 5mm, and others at 1cm. If you received a clear scan, there is no need for another to reconfirm, and doubt any other scanning would be done in absence of any suspicion. I had 10 PET/CT scans, which detected cancer when it was there, an MRI didn't one time.

Congratulations!