Dosimetric investigation of 3 different radiotherapy techniques in retrospectively with located in thoracic esophageal cancer patients

The aim of this study for thoracic esophagus cancers was to compare dosimetrically three dimensional conformal radiotherapy (3BKRT), intensity modulated arc therapy (YART), volumetric modulated arc therapy (VMAT), HYBRID treatment that combining of 3BKRT and VMAT and helical tomotherapy (HT) techniques. In addition, 5 treatment modalities were evaluated in terms of target volume, conformity index (CI), homogeneity index (HI), critical organs and monitor unit (MU). 10 patients' Computer Tomography images were taken from archive files were transferred to CMS XIO and Monaco treatment planning system (TPS) where treated curative radiotherapy in Uludağ University Medical Faculty Hospital for Esophageal cancer which is located in thoracic diagnosed. The target volume (GTV54, CTV50,4 and CTV45) and the critical organs (totallung, heart, spinal cord, liver, right-left kidney) are contoured for retrospective treatment planning. Simulation treatment plans were created in virtual envoriment with 5 different methods without any changes on the treated plans of the patients'. As a result of study, all treatment plans were found clinically acceptable but in terms of some critical organ doses, each technique gave different result compared to others. HIBRIT and 3BCRT techniques were demonstrated superior in terms of lung protection, HT technique did not provide the desired protection against low dose scattering in the lung, although it gave the most optimal value for other critical organs. The VMAT technique, the lowest MU values were observed, while providing adequate protection for parameters such as CI, HI and critical organ doses. In YART technique, expected limit values were obtained Key Words: 3DCRT, YART, VMAT, HYBRID, HT