Low energy deposition patterns in irradiated phantom with metal artefacts inside: a comparison between FLUKA Monte Carlo simulation and GafChromic EBT2 film measurements

Standard radiotherapy treatment planning software is not able to properly account for the presence of metal artefacts in the irradiation field, thus resulting in reduced accuracy of the treatment delivery to the tumor. To overcome this, Monte Carlo (MC) codes are used for the simulation of energy deposition in the target. In this study the feasibility of MC code FLUKA for the evaluation of low energy X-ray deposition patterns/dose distributions in the irradiated 3D printed anthropomorphic head and neck phantom with integrated metal artefact (metal tooth in the lower jaw) has been assessed comparing FLUKA simulations with experimental results, obtained when evaluating energy distribution patterns on irradiated EBT2 films. A good agreement between experimental and simulation results was found in general, however in field specific cases discrepancies with similar to 5% uncertainty was estimated. This indicates potential of FLUKA simulations for orthovoltage therapy applications, however the need for more accurate adjustment of FLUKA simulations must be considered.