POSITRON EMISSION TOMOGRAPHY IN THE EVALUATION OF LARYNGEAL CARCINOMA

Positron emission tomography (PET) is a relatively new radiologic imag ing technique based on glucose analog uptake and metabolism in tumor t issue. In this study, PET was used in evaluating 38 patients with lary ngeal cancer. Twenty-five patients were examined with PET prior to tre atment to study the reliability of PET in identifying the primary tumo r and assessing regional nodal status; 13 patients who had previously received irradiation with curative intent and who represented differen tial diagnostic problems were imaged to differentiate between irradiat ion effects and recurrent or residual cancer. Findings for both groups were compared to results of clinical evaluation and those of computed tomography (CT) and magnetic resonance imaging (MRI). The PET results were essentially identical to those of Cf, MRI, and clinical evaluati on in identifying metastatic lesions (82% correct), and were as reliab le as CT and MRI for correctly identifying primary tumors (88%). Posit ron emission tomography was most helpful in differentiating recurrent tumor from postirradiation tissue sequelae. However, its lack of anato mic detail made PET less valuable for primary staging and therapeutic planning. It may enhance the diagnostic accuracy of CT and MRI where a natomic distortions occur or where diagnostic criteria for CT and MRI are ambiguous.