Dosimetric Comparison of 3D-CRT, IMRT, IMAT and Helical Tomotherapy for Thoracic Esophageal Carcinoma

In this study, we compared the dose-volume parameters for treatment of thoracic esophageal cancer with treatment plans for 3D-CRT, IMRT, IMAT and HT. 15 thoracic esophagus patients who were treated in our clinic between 2017-2018 years were selected. PTV volumes were between 205 and 445.4 cc with an average of 355.2 cc. 3D-CRT, IMRT, IMAT and HT radiotherapy plans were created for each patient using the same contours and the same dose planning prescription. Total dose of 50.4 Gy for all patients was planed with 180 cGy dose per a fraction in total 28 fractions. For PTV; when the four treatment techniques were compared, HI values were 3D-CRT 0.84 ± 0.0, IMRT 0.57 ± 0.05, IMAT 0.06 ± 0.013, HT 0.08 ± 0.03 (p <0.05). CI values were found for 3D-CRT as 1.84 ± 0.2, for IMRT as 1.25 ± 0.05, for IMAT as 1.19 ± 0.04, for HT as 1.2 ± 0.06 (p <0.05). IMRT and IMAT techniques provided better OAR protection compared to other techniques in all lung and heart comparisons. The lowest doses for Dmax and D1% of Spinal Cord were provided by HT technique. We found that IMRT, IMAT and HT techniques have lower critical organ doses than 3D-CRT technique for treating torasic esophageal cancer. Considering the current evidence of the relationship between radiation-induced cardiac toxicity in the literature and the dose-volume parameters after treatment for esophageal cancer in our study, we can say that dose plans are better for IMRT and IMAT plans than 3D-CRT and HT in terms of lung and heart doses.