Dosimetric comparision of simultaneous integratad boost (SIB) and conventional radiotherapy dose plans localy advanced rectal cancer patients who underwent chemoradiotherapy

In this study, the treatment dose plans of conventional IMRT and SIB IMRT techniques of 42 patients with locally advanced rectal cancer were determined in HT TPS and compared with dosimetric methods. Dose plans were analyzed for PTV and critical organs. The analyzes were performed using SPSS 23.0 statistical software (IBM SPSS Inc. Chicago, IL, USA). All data were expressed as mean ± standard deviation. The comparisons were analysed by using Wilcoxon signed ranks test and Paired samples T test. A p value of <0.05 was considered significant for all statistical evaluations. As a result of the analysis, CI = 0.99 standard deviation 0.01 CI = 0.99 standard deviation 0.01 p = 0.243, HI = 0.04 standard deviation 0.02 HI = 0.06 standard deviation 0.02 p = 0.0001 was found for conventional IMRT and SIB IMRT PTVs, respectively. Critical organ doses for IMRT and SIB IMRT, small bowel V35 (15.7±12.40, 17.58±8.65 p =0.206) V40 (10.49±20.11, 4.18±3.82 p = 0.442) V45 (5.28±7.37, 5.02±5.30 p = 0.790), bladder V40 (36.00±15.84, 35.47±11.63) V45 (24.49±14.46, 24.76±12.73 p = 0.843) V50 (6.77±7.56, 4.68±4.75 p = 0.01) were found, respectively. The findings of this study showed that patients with HT could be treated in both conventional IMRT and SIB IMRT techniques by achieving similar dosimetric results. Keywords: Radiotherapy, preoperative local advanced rectal cancer, IMRT, SIB IMRT, Tomotherapy, TPS