Figures & data
Figure 1. Geometric field matching and feathering in CSI.
Figure 2. Comparison of proton and photon dose profiles used in this study. The numbers in the parenthesis are the 80–20% penumbral widths.
Figure 3. Comparison of dose profiles in the moving gap region between the brain and the spine fields for the three different gaps: 0, 2 and 4 mm, with (a) two 5 mm featherings, (b) two 10 mm featherings and (c) build up of the dose in the moving gap region with a 4 mm gap between the brain and the spine fields, and two 5 mm featherings. BF, brain field; Comp, composite dose; SF, spine field.
Figure 4. Comparison of dose profiles in the moving gap region between the superior and inferior spine fields for the three different gaps: 0, 2 and 4 mm, with (a) two 5 mm featherings, (b) two 10 mm featherings, and (c) build up of the dose in the moving gap region with a 0 mm gap between the spine fields, and two 5 mm featherings. Comp, composite dose; ISF, inferior spine field; SSF, superior spine field.
Figure 5. Comparison of dose profiles in the moving gap region for the various gaps between the brain and the spine fields for 6 MV photons with (a) two 5 mm featherings, and (b) two 10 mm featherings.
Figure 6. Comparison of proton and photon dose profiles in the moving gap between the brain and the spine fields. The proton profiles are shifted to match with the photon profiles for ease of comparison. (a) Matching proton profile with 0 mm gap and 10 mm feathering with selected gap and feathering widths for 6 MV photons. (b) Matching proton profile with 0 mm gap and 5 mm feathering with a selected gap and feathering widths for 6 MV photons.
Figure 7. Comparison of dose distributions in (a) photon and (b) proton CSI. The advantage of proton CSI is the absence of exit dose in the thorax region.
