Evaluation study of using three different algorithms in intensity modulated radiotherapy technique for breast tumors

Our aim is to evaluate and compare between three different dose calculations algorithms (fast superposition (FSUP), superposition (SUP), and convolution (CON)) in IMRT (intensity modulated radiotherapy) treatment planning technique for breast cancer patients. Ten patients with left-side breast cancer were selected for this study. Dose of 5000 cGy was prescribed to planning target volume (PTV). For each patient, IMRT plans were created with non-coplanar and non-opposing photon beams of 6 MV quality. CMS XiO system of treatment planning (TPS) was the system for the process of planning. The percent of maximum variation observed between the three algorithms for PTV was 2.33% in average conformity index (CI), and for OARs was 2.68% in average Dmean in case of contralateral breast. Significant variations between three algorithms were observed. Due to our study, because the results between the three different algorithms show clear difference in some comparisons, considerable precaution unavoidable in treatment plans evaluation, because the dose calculation algorithm selection could effect on the process of treatment planning (TP) and also on the end medical results.