[Positron emission tomography in head and neck oncology]

Defining a therapeutic strategy in oncology requires a substantial amount of imaging data provided by modern techniques. While the description of the lesions and their environment has become very precise, there remains a certain degree of uncertainty concerning tissue typing. Positron emission tomography is a scintigraphy technique which can produce quantitative images of metabolic characteristics. 18F-fluorodeoxyglucose is a tracer allowing an analysis of glucose metabolism known to be highly increased in malignant tissues. Increased uptake is an indication of malignancy with an established correlation with proliferative capacity. The only limitation of the method is the generally weak uptake observed in benign hypermetabolic inflammatory or infectious areas. All stages of the disease are concerned for head and neck cancer patients. Clinical experience to date indicates that PET can be applied most usefully to search or residual disease with a possible differentiation between post-therapeutic fibrosis and viable tumor tissue as well as the identification of early relapse. Study of early response to chemotherapy is also an interesting application. Search for extension can also be improved with this technique allowing both regional and whole body explorations. Positron emission tomography is not widely available in France at the present time so all patients cannot be examined with this technique. Positron emission tomography is an evolving technique with improvements being proposed both in the technique and in tracer elements. Further information will be available with new developments in this non-invasive exploration tool.