Table 4 Dose-volume constraints and objective functions used in uniform-dose planning. † = Quantitative Analyses of Normal Tissue Effects in the Clinic (QUANTEC). *Radiation Therapy Oncology Group (RTOG) Consensus. Square deviation function penalises any deviation from the reference dose, Dref, whereas square overdose function penalises doses greater than Dref. Mathematical formulations of the objective functions are summarised in Appendix 2
Volume of interest | DV constraint | Objective function | Function parameter(s) |
|---|---|---|---|
CTV | V78Gy ≥ 99% | Square deviation | Dref = 78 Gy |
Rectum†[39] | V50Gy ≤ 50%, V60Gy ≤ 25% | DV | Dref1 = 50 Gy and Vref = 50%, Dref1 = 60 Gy and Vref = 25% |
Bladder†[61] | V65Gy ≤ 50% | DV | Dref1 = 65 Gy and Vref = 50% |
Left and right head of femurs (HOF)* [36] | V50Gy ≤ 5% | DV | Dref1 = 50 Gy and Vref = 5% |
External volume | – | Square overdose | Dref = Variable to avoid hotspots |