Optimization of the modelling of longitudinal dose distributions for double-scattered proton beams in a commercially-available treatment planning system

The configuration of a treatment planning system (TPS) for double-scattering-based proton therapy requires many user inputs. Most of these are either gathered during the routine collection of commissioning data, or can be supplied by the equipment vendor; however, this is not true of all. In this study we developed a technique both to (a) expedite the extraction of those undetermined TPS parameters related to the range modulator wheels that can only otherwise be obtained by the time-consuming process of trial-and-error, and (b) demonstrate how, for a commonly-employed, commercially-available TPS, the judicious determination of such parameters can be used to optimize the resultant modelling of longitudinal dose distributions delivered by a double scattering proton therapy system. Our technique is simple to implement, robust in nature and also provides insight allowing parameters that must be contrived in that model to be related directly to physical aspects of the beam delivery system.