Evaluation of CorePlanTM treatment planning system for 6 and 15 MV photon irradiation

Introduction: Radiotherapy is an effective modality to treat esophageal carcinoma. Due to various inhomogenous tissues with a variety of physical and radiological properties which can cause uncertainty in accurate dose calculations in radiation therapy, accuracy of TPS is very important. The aim of this study was to quantify dose calculation accuracy of CoreplanTM TPS in an inhomogenous home-made phantom.   Materials and Methods: Thermoluminescent dosimeter-100 (TLD-100) chips were used within inhomogeneous home-made phantom for dose measurement; CoreplanTM was also applied for dose calculation. Finally, difference between measured doses and calculated doses was gotten to calculate dosimetry accuracy of the TPS at PTV and neighbor’s organ at risks region.   Results: Findings indicated that for regions near PTV, Coreplan TPS leads to an overdose estimation up to 2.3% and 4.8% for the 6 and 15 MV energies, respectively and in regions far from primary field, the Coreplan TPS underestimated the dose compared to the measurements which might be due to scattered radiation that is not well considered in the TPS.   Conclusion: Due to the inhomogeneous in the thorax region, the dose calculation accuracy of TPS should be appropriate. The agreement criterion was determined according to ICRU recommendation, which suggest the accuracy of ±5% in the delivery of an absorbed dose to a target volume. According to the results, it is concluded that the accuracy of dose calculation of Coreplan TPS showed good agreement with experimental data.