Simultaneous integrated boost IMRT in pediatric: evaluation for two commercial treatment planning systems

Objective The aim of the work was to compare the dosimetric results that were obtained by using two treatment planning systems (TPS) Siemens KonRad version 2.2.23, Elekta XiO version 4.4 to perform a simultaneous integrated boost (SIB) for head and neck and central nervous system (CNS) cases in paediatric patients. Methods The CT scan data for five paediatric patients, with head and neck and CNS tumors, were transferred into both of the TPSs. Clinical step-and-shoot intensity-modulated radiotherapy (IMRT) treatment plans were designed using 6 MV photon beam for delivery on a Siemens Oncor Accelerator with multileaf collimator MLC (82 leaf). Plans were optimized to achieve the same clinical objectives using the same beam energy, number and direction of beams. The analysis was based on isodose distributions, the dose volume histogram (DVH) for planning target volume (PTV) and the relevant organs at risk (OARs) as well as volume receiving 2 Gy and 5 Gy, also total number of segments, MU/segment, and the number of MU/cGy had been investigated. Treatment delivery time and conformation number were two other parameters in this study. Results The segmentation using KonRad was more efficient, resulting in fewer segments (reduction between 13.2% and 48.3%), fewer MUs (reduction between 10.7% and 33%) and that reflected on treatment delivery times to be shorter by up to 8 min or 46%. In most of the cases KonRad had the highest volume receiving in excess of 2 and 5 Gy, and XiO showed the lowest. Also KonRad achieved slightly better conformality (0.76 ± 0.054) than XiO (0.73 ± 0.05) while XiO presented a higher modulation factor value (3.3 MU/cGy) than KonRad (2.4 MU/cGy). Conclusion The KonRad treatment planning system was found to be superior to the XiO treatment planning system. This is true for the possible increase of radiation-induced secondary malignancies as well as for the local control.