Figure 2.

Example images of fiducial motion and DRR to kV registration; flow chart of pre-treatment image registration. a. A typical pre-RT CBCT registered to planning CT using skeletal landmarks. b. Fiducial displacement from planning CT to CBCT with skeletal alignment for a pancreas patient. c. Fiducial displacement from planning CT to CBCT with skeletal alignment for a liver patient. d-e. an example of kV orthogonal images with fiducial matching to the contour derived from DRR. f. Flow chart describes how the imaging guidance was performed before the treatment and how the shifts were resolved.