Prospective randomized double-blind study of atlas-based organ-at-risk autosegmentation-assisted radiation planning in head and neck cancer

Background and purpose: Target volumes and organs-at-risk (OARs) for radiotherapy (RT) planning are manually defined, which is a tedious and inaccurate process. We sought to assess the feasibility, time reduction, and acceptability of an atlas-based autosegmentation (AS) compared to manual segmentation (MS) of OARs. Materials and methods: A commercial platform generated 16 OARs. Resident physicians were randomly assigned to modify AS OAR (AS + R) or to draw MS OAR followed by attending physician correction. Dice similarity coefficient (DSC) was used to measure overlap between groups compared with attending approved OARs (DSC = 1 means perfect overlap). 40 cases were segmented. Results: Mean +/- SD segmentation time in the AS + R group was 19.7 +/- 8.0 min, compared to 28.5 +/- 8.0 min in the MS cohort, amounting to a 30.9% time reduction (Wilcoxon p < 0.01). For each OAR, AS DSC was statistically different from both AS + R and MS ROIs (all Steel-Dwass p < 0.01) except the spinal cord and the mandible, suggesting oversight of AS/MS processes is required; AS + R and MS DSCs were non-different. AS compared to attending approved OAR DSCs varied considerably, with a chiasm mean +/- SD DSC of 0.37 +/- 0.32 and brainstem of 0.97 +/- 0.03. Conclusions: Autosegmentation provides a time savings in head and neck regions of interest generation. However, attending physician approval remains vital. (C) 2014 Elsevier Ireland Ltd.