Fig 1.
Irregularly-shaped target volumes for abdomen (a), head and neck (b), and chest cases (c).
Table 1.
Patient characteristics.
Fig 2.
An example of area size difference between the integrated multi-leaf collimator (MLC) aperture and collimator settings with 5 mm-margins to the integrated MLC aperture with respect to collimator angles in the case of an angular section of 40°.
Collimator angles were rotated at intervals of 2° ranging from 0° to 90°. Red (square) points for each sectional arc were minimum area size differences.
Table 2.
The values of optimal collimator angles for each of sectional arcs for abdominal case.
Fig 3.
Examples of dose-volume histograms of target volumes and normal organs for abdomen cases (a), head and neck cases (b). The DVHs of Colli-VMAT plans with an angular section of 40° (Colli-VMAT (40°)) and Std-VMAT plans (Std-VMAT (360°)) are plotted with bold lines (solid and dashed) while those of Colli-VMAT plans with angular sections of 60°, 90°, and 120° (Colli-VMAT (60°), Colli-VMAT (90°), and Colli-VMAT (120°)) are plotted with dotted, dash-dotted, and dash-dot-dotted lines, respectively.
Table 3.
Average dose-volumetric parameters of abdominal cases.
Table 4.
Average dose-volumetric parameters of head and neck cases.
Table 5.
Average dose-volumetric parameters of chest cases.
Fig 4.
The average values of total MU reduction with respect to Colli-VMAT plans with angular sections of 40°, 60°, 90°, and 120° (Colli-VMAT (40°), Colli-VMAT (60°), Colli-VMAT (90°), and Colli-VMAT (120°)), and Std-VMAT plan (Std-VMAT (360°)) for abdomen, head and neck, and chest cases.
Table 6.
Mean total MUs for abdominal, head and neck, and chest cases.
Fig 5.
Beam’s-eye view (BEV) of the target volume which has a concave shape fitted by multi-leaf collimators (MLCs) at collimator angles of 0° (a) and 90° (b).