Fig. 4

Boxplots of CT/MR registration (blue) and MR-only registration (red) showing the variation between the seven observers in (a) RL translation and (b) rotation around the RL axis per patient, mean set to zero. Boxplots show the interquartile range. Whiskers indicate the outermost points within 1.5 × IQR and the points beyond that are outliers. Histograms showing the variation in (c) RL translation and (d) rotation around the RL axis of seven observers pooled over the patient population (n = 20). CT/MR registration (blue), MR-only registration (red), overlaying histograms appear purple