Fig. 3

Boxplot shows the relationship between the upper mesorectum volume on CBCT relative to the planning CT scan with selected margin. It shows the interquartile range, with a horizontal line showing the group median. Whiskers indicate the 5th and 95th percentiles. Outliers are marked. One-way ANOVA testing with Bonferroni correction applied showed all margins to be significantly different (p < 0.001)