Fig. 6

The relation between registration time and the clinical target volume (CTV) center of mass (CoM) vector displacement for observer 1 (circles), observer 2 (triangles), observer 3 (squares) and observer 4 (plus signs). Time is displayed in seconds on the x-axis and the CTV CoM vector displacement in mm on the y-axis. All observers were represented in the range of displacements and times. Observer 1 was clearly in the lower range of registration times, also seen in Fig. 5, but was not exclusively part of the lower nor higher range of CTV displacements