A semi-empirical approach for independent dose calculations for complex teletherapy treatments

The need for high accuracy of physical simulations in radiation therapy has put aside more simplistic methods for dose calculation. However, the complexity and the computation times make simulations less practical for an independent verification of dose calculation. In this work we describe a novel algorithm which allows assessment of the dose in a specific point of the treatment plan. We developed a relationship that models the contribution to the final dose from two components: dose delivered by charge particles which are the result of the first interaction of radiation with the environment, and dose delivered by charge particles which are the result of scattered radiation. To validate our algorithm, we compared it with a highly-accurate computerized treatment planning system (TPS) and with dose measurements of 45 challenging treatment plans. We found that the relative differences against both, TPS and measurements, were less than 4% except for breast cancer plans, where differences were higher than 10% due to the irregularity of radiation fields. In conclusion, we developed a novel and robust method for dose calculation which has easy application and provide sufficient accuracy and dose interpretability for independent verification of dose calculation in radiation therapy.