Figure 3. Subjective and objective comparisons of auto-generated influencer and target contours with human-generated contours.

(A) Histogram of overall subjective quality of auto-contoured influencers, rated from 1-5 where 1 is unacceptable delineation of the organ (i.e., majority of the auto-contour is outside the organ, or majority of the organ is outside the auto-contour), 3 is moderate modifications required to accurately represent the organ (i.e., auto-contour moderately over-contours or under-contours the organ), and 5 is perfect delineation of the organ without modification. (B) Breakdown of subjective quality by organ (top) and treatment progress (bottom). Auto-contoured mandible was found to be worse quality subjectively than the other three, and the auto-contour subjective quality dropped at later radiotherapy fractions. (C) Table of overall objective quality of auto-contoured influencers compared to human-contoured counterpart, assessed with dice similarity coefficients (DSC), mean Hausdorff distances, and 95% Hausdorff distances (HD95%). (D) When grouped by treatment progress, auto-contoured target DSC was found to worsen with treatment progress (p = 0.033). (E) DSC and HD95% for each of the four auto-contoured organs were similar, signifying the auto-contouring algorithm did not perform better for any one organ versus others. (F) When grouped by treatment progress, influencer auto-contour HD95% was found to increase near the end of the treatment. This indicates auto-contour quality worsens at later radiotherapy fractions.