Wanted to share my history of scans, not to scare, but to encourage you to ask if it does not feel right.
Prior to dx I had an ultra sound - showed an ill defined area in submandibular gland. That promted a CT which showed nothing, specificaly nothing in or around the gland. Several doctors later had a MRI, also neg, specifically around the galnd. A few doctors later had FNA ultrasound guided biopsy of ill defined area identified in ultrasound. Positive for AdCC. Heres the kicker. After they knew what and where it was, I had a PET scan and it didn't show up.
The only imaging technique that picked up on my 3.4cm tumor was a ultrasound.