The flow process diagram regarding calculation of the CTV.

<p><i>CTV: clinical target volume.</i></p

Inter- and intra-observer variability.

<p>(A) Inter-observer variability in the multiple contours from five observers; (B) Intra-observer variability involving a single physician at different times.</p

Comparison of the time required to generate the clinical target volume between the newly developed method and the traditional method involving manual modification.

<p>*millimeter;</p><p>**second.</p

Schematic diagram of growth iterations.

<p>Schematic diagram of growth iterations.</p

Inter- and intra-observer variability in the delineated volume and conformity index using the traditional method for generating the clinical target volume.

<p>Inter- and intra-observer variability in the delineated volume and conformity index using the traditional method for generating the clinical target volume.</p

Two-dimensional images (A–B) and 3D visualization (C–F) results from the CTV delineation in different situations.

<p>(A) The model of isotropic external expansion using the direct Euclidean distance calculation; (B) The model of anisotropic external expansion involving the use of the geodesic distance calculation to automatically cross the cerebral falx; (C) Generating the CTV without taking into consideration the cerebral falx or skull; (D) Considering the cerebral falx but not the skull; (E) Considering the skull but not the cerebral falx; (F) Considering both the skull and the cerebral falx. <i>The deep red area represents the GTV, the blue area the cerebral falx, the grey area the skull, and the pink area the CTV. GTV: gross tumor volume; CTV: clinical target volume.</i></p