Is it reasonable to expect that, after a course of chemotherapy, a patient should be PET-scanned to ensure that the treatment has been effective? I realise that PET-scanning is an expensive process, but the assumption that a particular chemotherapy approach will eliminate the tumour at which the treatment is directed is a hopeful, but not definative, approach.  Surely chemotherapy should be followed by PET-scanning as a confirmation that chemotherapy has been a success?