Fig. 3.
The prescribed dose and predicted TCP for single-fraction IDP with the V12Gy = 10 cm3 constraint as a function of the GTV diameter for coplanar and non-coplanar beam arrangements with a GTV-PTV margin of 0–2 mm and spherical GTVs. Legend: Gy Gray, GTV gross tumor volume, TCP tumor control probability, IDP isotoxic dose prescription, V12Gy volume of healthy brain tissue which is irradiated to 12 Gray or more, PTV planning target volume. A GTV-PTV margin enlargement results in an increase of the PTV size. An increase in the PTV size results in different cut-offs with a PTV size-based dose prescription with 24, 21, 18, and 15 Gy. The diamond (green line), circle (blue line), and cross (red line) represent the cut-offs with dose prescriptions with GTV-PTV margins of 0, 1, and 2 mm, respectively