Figure 2From: Investigation of the change in marker geometry during respiration motion: a preliminary study for dynamic-multi-leaf real-time tumor trackingThe distal bronchus and the center of gravity of the tumor. Note that the distal bronchus is not visible, but can be detected by VBPA (yellow arrow). The center of gravity (blue arrow) was estimated by delineating the tumor contours (blue) at each respiratory phase on ImageJ.Back to article page