TOC graphs reconstructed from systematic literature review. TOC graphs showing (A) the trade-offs between TCP and either NTCPGI (blue) or NTCPGU (red) over the dose range of 60–80 Gy in 2 Gy fractions (solid curve) and the extrapolated dose ranges (dashed curve). In (B) the dashed line represents the tangent where TCP and NTCPGI equally increase with dose and defines the optimum of P
= TCP - NTCP (○). Dose levels in 2 Gy fractions are indicated (●) along the curve.