FIG. 1.

(a) Surface registration. S_src: source surface from planning CT, S_trg: target surface from treatment CBCT, ${\mathit{S}}_{\mathrm{src}}^{\prime }$: transformed source surface calculated by surface registration, T_s: transformation matrix calculated by surface registration, (b) Volumetric registration. V_src: source volume data from planning CT, V_trg: target volume data from treatment CBCT, ${\mathit{V}}_{\mathrm{src}}^{\prime }$: transformed source volume data by volumetric registration, T_v: transform matrix by volumetric registration, and (c) Flowchart of the surface and volumetric registrations.