OK, it's not the18F DCFPyL scan being offered but the F18 FDG. As Lyn says, suitability can vary with patient, and I think best decided by Oncologist/Radiologist. About 8% of men do not express sufficient PSMA for the 68 Ga scan to work for example. An important factor generally is where any escaped cancer cells might have migrated to and whether these are in concentrated clumps or are more finely distributed. That latter makes it difficult to locate as you would expect, even with the best scans.