CT-based parotid gland location: implications for preservation of parotid function.

Abstract

The position of the parotid gland in relation to surrounding structures was investigated. Sixty-five patients with head and neck tumours were prospectively evaluated. Parotid position was determined using beam's eye views of CT images projected on simulator films. Distances between the different borders of the parotid gland and surrounding bony marks were quantitatively assessed. The parotid gland volume ranged from 12.9 to 46.4 cm(3). The distance between the cranial border of the parotid gland and the tuberculum anterior of the atlas ranged between 0.7 and 4.8 cm. The position of the parotid gland was unaffected by the angle of the mandible. The size and position of the parotid gland varies largely among patients. As the extent of radiation-induced salivary dysfunction depends on the volume of the gland tissue exposed, CT-based simulation of radiation fields is necessary.