I've not heard of getting a PET scan prior to TURBT (Transurethral Resection of Bladder Tumor) aka biopsy.
I think they can tell how deep to cut based on what they see when they are in there. However, not getting enough margin (tissue around the tumor) is a common problem so a second TURBT is recommended for six weeks after the first.
If the first TURBT isn't done at a major bladder cancer center (it should be), then at least the follow up TURBT should be.
I had a PET scan after I had a recurrence a couple of years after my initial diagnosis and treatment but that was only after urine cytology came back positive for high grade cancer and they were pretty sure it had spread (it hadn't).
Mike
Age 54
10/31/06 dx CIS (TisG3) non-invasive (at 47)
9/19/08 TURB/TUIP dx Invasive T2G3
10/8/08 RC neobladder(at 49)
2/15/13 T4G3N3M1 distant metastases(at 53)
9/2013 finished chemo -cancer free again
1/2014 ct scan results....distant mets
2/2014 ct result...spread to liver, kidneys, and lymph...