Dosimetric comparison of modern radiotherapy techniques for gastric cancer after total gastrectomy

Purpose: The purpose of this study is to investigate the optimal radiotherapy technique for postoperative irradiation of gastric cancer treated with total gastrectomy. Materials and Methods: The database of ten patients was used for this study. Three-dimensional (3D) conformal radiotherapy, intensity-modulated therapy (IMRT), volumetric modulated arc therapy (VMAT), and helical tomotherapy (HT) plans were created for each dataset. The prescription dose was 45 Gy in 25 fractions. Comparative analyses of the target volume coverage and the doses of organs at risk were performed. Results: HT was significantly provided more homogeneity. The best conformal plans were achieved with VMAT. Both kidneys were better preserved with HT and VMAT. HT significantly lowered the V13 of the left kidney and VMAT significantly lowered V20. However, the mean left kidney doses were not statistically different. The lowest liver V30 was obtained with VMAT but not with statistically different than IMRT and HT. Mean liver doses were statistically inferior with 3D. The worst spinal cord doses were seen with 3D. The integral dose of the body did not differ among the techniques. Conclusion: In comparison of the four techniques, 3D seems to be the most unsuitable method regarding sparing the normal tissues. According to availability, HT and VMAT should be primarily preferred. IMRT can also be used with carefully paying attention to the clinical condition of the patient.