Development of a standardized method for contouring the larynx and its substructures

Abstract

ObjectivesLimiting radiation dose to the larynx can diminish effects of laryngeal dysfunction. However, no clear guidelines exist for defining the larynx and its substructures consistently on cross-sectional imaging. This study presents computed tomography (CT)- and magnetic resonance imaging (MRI)-based guidelines for contouring laryngeal organs-at-risk (OARs).Materials and MethodsStandardized guidelines for delineating laryngeal OARs were devised and used to delineate on CT and MRI for head-and-neck cancer patients. Volumetric comparisons were performed to evaluate consistency and reproducibility of guideline-based contours.ResultsFor the initial 5 patients the mean CT and MRI based larynx volume did not differ significantly between imaging modalities; 34.39 ± 9.85 vs. 35.01 ± 9.47 (p = .09). There was no statistical difference between the CT based mean laryngeal volume in the subsequent 44 patients compared to the initial 5 patients outlined on CT and the MRI scan (p = 0.53 and 0.62). The OAR volume for laryngeal substructures were not statistically different among patients or between imaging modalities. Once established, the guidelines were easy to follow.ConclusionThe guidelines developed provide a precise method for delineating laryngeal OARs. These guidelines need to be validated and clinical significance of outlining laryngeal substructures and dose-volume constraints should be investigated before routine implementation in clinic practice.

Use of a novel atlas for muscles of mastication to reduce inter observer variability in head and neck radiotherapy contouring

“…Contouring atlases can help standardise volumes, reduce interobserver variability and improve normal tissue sparing in daily clinical practice [8][9][10][11]. Atlases agreed by an expert panel may reduce inconsistencies between radiotherapy centres and facilitate multi-institutional clinical trials [12].…”

Defining the dose‐volume criteria for laryngeal sparing in locally advanced oropharyngeal cancer utilizing split‐field IMRT, whole‐field IMRT and VMAT

“…This study also highlights the need for consensus contouring guidelines regarding the larynx and sub‐sites for radiotherapy plan evaluation as well as for longitudinal impact of radiation dosing on long‐term swallowing function. Although the larynx is a known at‐risk organ for post‐treatment radiation‐induced dysphagia, there is a paucity of published guidelines for contouring of the larynx and laryngeal substructures and their and dose‐volume constraints for swallowing dysfunction 23 . Our study has several findings that are noteworthy for clinical application.…”

Stereotactic body radiotherapy for T1 glottic cancer: dosimetric data in 27 consecutive patients

“…The reader should be aware of limitations of the present study. First, for the delineation of the larynx and its substructures, we followed consistently the available atlases, 13,14 but we cannot exclude that differences exist in contouring among institutions. Second, dose calculation accuracy might be an issue when small volumes and tissue dishomogeneities are involved.…”

“…OAR included the following: spinal cord, whole larynx, 13 contralateral TVC (cTVC), ipsilateral and contralateral arytenoid cartilages (iAC and cAC), 14 thyroid cartilage (TC), 14 cricoid cartilage (CC), 14 esophagus, hypopharynx (including also the inferior constrictor muscle), thyroid gland, and ipsilateral and contralateral carotid arteries (iCA and cCA, respectively).…”