Evaluating Performance of Algorithms in Lung IMRT: A Comparison of Monte Carlo, Pencil Beam, Superposition, Fast Superposition and Convolution Algorithms

Background: Inclusion of inhomogeneity corrections in intensity modulated small fields always makes conformal irradiation of lung tumor very complicated in accurate dose delivery.Objective: In the present study, the performance of five algorithms via Monte Carlo, Pencil Beam, Convolution, Fast Superposition and Superposition were evaluated in lung cancer Intensity Modulated Radiotherapy planning.Materials and Methods: Treatment plans for ten lung cancer patients previously planned on Monte Carlo algorithm were re-planned using same treatment planning indices (gantry angel, rank, power etc.) in other four algorithms.Results: The values of radiotherapy planning parameters such as Mean dose, volume of ۹۵% isodose line, Conformity Index, Homogeneity Index for target, Maximum dose, Mean dose; %Volume receiving ۲۰Gy or more by contralateral lung; % volume receiving ۳۰ Gy or more; % volume receiving ۲۵ Gy or more, Mean dose received by heart; %volume receiving ۳۵Gy or more; %volume receiving ۵۰Gy or more, Mean dose to Easophagous; % Volume receiving ۴۵Gy or more, Maximum dose received by Spinal cord and Total monitor unit, Volume of ۵۰ % isodose lines were recorded for all ten patients. Performance of different algorithms was also evaluated statistically.Conclusion: MC and PB algorithms found better as for tumor coverage, dose distribution homogeneity in Planning Target Volume and minimal dose to organ at risks are concerned. Superposition algorithms found to be better than convolution and fast superposition. In the case of tumors located centrally, it is recommended to use Monte Carlo algorithms for the optimal use of radiotherapy.Â

Keywords:

Monte Carlo , Lung IMRT , Algorithms , Pencil Beam , Superposition , Dose to OARs