(Radio)Biological Optimization of External-Beam Radiotherapy

Figure 7

Dose-volume histograms for a radiobiologically guided inverse plan (3-field IMRT) aiming to maximize TCP for the same NTCP (labelled as “Bio-Plan (isotoxic)”) compare to a standard (3-field) treatment plan delivering 55 Gy (in 20 daily fractions) to a NSC lung tumour. The target volume (PTV, GTV) doses are more heterogeneous in the radiobiological plan. The increases in TCP values for the standard and radiobiologically optimized plans are also shown; the TCP parameters are from Nahum et al. [37]—see the subsection on “Level I” BIOP.