ORANGE, a new, fast dose engine for radiotherapy treatment planning.

A new Monte Carlo dose engine is introduced under the name of ORANGE. It is a general purpose and flexible program, because it is based on MCNP, and it is fast, because a fast dose algorithm has been added to it. In this paper it is shown that the dose results for photons and electrons are accurate within 2%, and that ORANGE can calculate accurate three-dimensional dose distributions in a 30 x 30 x 30 cm3 phantom with 60(3) voxels within a quarter of an hour on present day PCs, even before employing variance reduction techniques.