Why most PET of lung and head-and-neck cancer will be PET/CT

Experience in our and other institutions with PET/CT imaging of lung and head and neck cancers has shown that this new modality has higher specificity and sensitivity than PET alone and in certain settings even when compared to PET and CT viewed side by side. The largest experience exists with non-small cell lung cancer (NSCLC), in which it has been demonstrated that PET/CT is superior to PET and CT in T and in N staging. Superiority in M staging has yet to be demonstrated. CT contrast media enhancement is probably only necessary when a substantial mediastinal tumor component is present. In such cases, delineation of tumor from vascular structures is relevant. In ENT tumors, PET/CT also appears to be superior to PET, and probably also to PET and CT viewed side by side. Early information suggests that contrast media enhancement for staging may not be required, but the data available is still limited. In both settings, it is interesting to note that in a number of patients, second metachronous tumors are discovered with PET/CT, mainly localized in the GI tract.