The effect of the different uncertainty models in dose expected volume histogram computation.

Dose expected volume histograms are a useful alternative to dose volume histograms in order to take into account computation uncertainty when prescribing, planning and reporting external beam radiation therapy. Due to the type B nature of computation uncertainties, a rectangular probability distribution was assumed in its definition. In the present work, the changes of dose expected volume histograms when using other recommended point dose uncertainty models are investigated. Results show that the choice of probability distribution, among the ones recommended for uncertainty modelling, has a small effect on the result. Thus, the standard uncertainty of point dose computations is the main parameter affecting dose expected volume histograms.