Role of PET-CT in GU Tract:

Low sensitivity for primary tumor detection

Sensitivity 60%, specificity 100%
Many RCCs are isointense to renal parenchyma
Urine excretion can mask tumor adjacent to collecting system, False- negatives


Lymphadenopathy

Regional nodal metastases usually hypermetabolic


Distant metastases

Most common
Lung
Liver
Bone
Brain
Usually F-18 FDG avid
Sensitivity 34-90%, specially 75-100%
Useful for postoperative surveillance and restaging



Can miss mets in liver and brain due to physiologic F-18 FDG uptake
o Prognostic value unclear

SUV has not been shown to correlate with histologic type or nuclear grade
No difference in survival time of PET- positive PET-negative patients

Ga-68 PSMA PET/CT Findings

PSMA: Membrane protein highly expressed in prostate cancer and other solid tumors

Expressed in 80-100% of clear cell RCC tumors


Effective in detecting metastatic lesions in patients with known RCC

Better sensitivity, can find smaller metastases that are undetectable by conventional CT
Changes surgical management


Can be used in patients with renal impairment or contrast allergy