A pragmatic contouring guideline for salivary gland structures in head and neck radiation oncology: The MOIST target

OBJECTIVES:: One of the main normal tissue toxicities in head and neck radiation oncology is xerostomia. In several studies, reduced radiation dose to the salivary glands has been shown to diminish the effects of gland dysfunction. However, no clear guidelines exist to define the anatomic location of the involved glands on cross-sectional imaging in a pragmatic manner. This study presents an anatomic, computed tomography (CT)-based definition of the major and minor salivary glands. METHODS:: On the basis of information from normal structure anatomy, the location of major and minor salivary glands was identified and translated into a cross-sectional CT-based description of the salivary glands. RESULTS:: The major salivary glands include the parotids and submandibular glands. The minor salivary glands are presented as a part of a surrogate structure (the Minor Oral Including Sublingual Salivary Tissue target), including the minor glands located in the oral mucosa of the tongue, hard and soft palate, buccal mucosa, and inner surface of the lips. CONCLUSIONS:: Clinical implementation of CT-based delineations of the salivary glands according to the proposed guideline should reduce interobserver variability. This may lead to an improved understanding of the relationship between radiation dose and volume and effects on salivary function.