I am not a doctor, but using a PSMA PET scan for initial staging does not make sense. That scan only detects cancer cells that express PSMA, and does not detect other cancers that don't. It can't reveal "many more other cancers," as you put it. It seems like an MRI and a non-PSMA PET scan would be more useful because they can detect more types of cancer than just those cells that express PSMA.