PET scans are often given after the initial biopsy to determine if the cancer has spread. Oral cancer typically spreads first to lymph nodes in the neck. If you have trauma to your tongue such as a biopsy, you could have some reactive nodes in the neck which could show up on the PET scan. I was told to wait 3 months after a procedure and between PET scans to minimize the risk of a false positive. However, 3 months is too long to wait under these circumstances. I don't believe an MRI has this issue, so if the doctor is recommended both I think that is a good idea. If any nodes do light up on the PET scan, the doctor will likely recommend a neck dissection to remove some of the nodes. This is a fairly common procedure with OC patients.

I've been dealing with OC since 2005, a recurrence, dysplasia, 4 surgeries plus countless tests, and multiple opinions each step of the way after the 1st surgery. In my opinion I would have the scans and postpone the next surgery until those results are know. 1 to 2 weeks isn't that long, unless your cancer is very aggressive. I don't have a medical background so discuss this with your medical team.

I believe in your other posts in your other thread, one doctor mention doing frozen sections. My last 2 surgeries were at Johns Hopkins and they did frozen sections during the surgery - it is a quick biopsy of areas of concern done during the surgery. I would push for this, while not 100 percent accurate, it does increase the likelihood they would "get it all" during the next surgery.

Don't worry too much about posting your question in the right forum, but it would be better to post all your question in one thread. It helps us understand your issues and concerns are in one place. Perhaps one of the admin folks could combine the 2 threads?

If you have the PET scan, you should be given instructions on what to eat before the scan (I believe low carb, high protein) and avoid exercise. I don't recall the whole list (would have to look for it), but this helps minimize false positives also.