Delineation of Radiation Therapy Target Volumes for Lingual Nerve Involvement.

It is important for radiation oncologists to be able to accurately contour the lingual nerve pathway, as it is commonly involved in oral cavity cases. However, most atlases do not give a detailed account of the entire lingual nerve pathway as it traverses from the oral cavity, through the masticator space, to the base of the skull. Three experienced head and neck cancer specialists (two radiation oncologists and one neuroradiologist) examined anatomy textbooks, institutional magnetic resonance imaging (MRI), and computed tomography (CT) images of normal anatomy and also recurrences along the lingual nerve pathway to determine "anchor points" to help radiation oncologists contour more confidently. We found five anchor points to help radiation oncologists contour the lingual nerve pathway: At the level of the foramen ovale, the lateral pterygoid, the transition between lateral and medial pterygoid, the medial pterygoid (within the pterygomandibular space), and the oral cavity. Five anchor points with easily identifiable anatomy are established that radiation oncologists can use to contour the lingual nerve pathway more confidently.