CEA is definitely not (yet) for clinical use, i.e. treating sick people routinely. It's for clinical research, i.e. scanning sick or healthy people, potentially

CEA is definitely not (yet) for clinical use, i.e. treating sick people routinely. It's for clinical research, i.e. scanning sick or healthy people, potentially (if and only if in the context of a registered clinical trial) changing their treatment as a corollary.