Fig. 1From: Tumor motion changes in stereotactic body radiotherapy for liver tumors: an evaluation based on four-dimensional cone-beam computed tomography and fiducial markersFour-dimensional cone-beam computed tomography (4D-CBCT) images of the end-exhalation a, c and end-inhalation b, d. The “internal marker target volume (IMTV)” structure (blue and orange) that reflected the motion of fiducial markers observed in 4D-CBCT were used for target localization in liver SBRTBack to article page