Delineation guidelines for organs at risk involved in radiation-induced salivary dysfunction and xerostomia.

BACKGROUND AND PURPOSE It is believed that minimizing inconsistencies in OAR-volume definition will help to improve adequate reporting and interpreting of radiation treatment results. The aim of this paper is to introduce computed tomography (CT)-based delineation guidelines for organs at risk (OARs) in the head and neck area, associated with radiation-induced salivary dysfunction and xerostomia. MATERIAL AND METHODS After analyses of the human anatomy of the head and neck area, computed tomography (CT)-based guidelines for delineation of the most relevant OARs were described by a panel of experts. RESULTS AND CONCLUSIONS The provided OAR guidelines are accompanied by CT-based illustrations presenting examples of the delineated structures and their corresponding anatomic boundaries. The parts of the tongue bearing minor salivary glands could not be outlined. Difficulties and uncertainties in defining these minor salivary glands on CT remain to be resolved. Implementation of these guidelines in practice should lead to a reduction in inter- and intra-observer variability and therefore unambiguous reporting of possible dose-volume effect relationships.