Comparison of different calculation indexes with dosevolume histogram parameters for evaluation ofradiation treatment plans in gynecologic malignancies

Background: we aimed to investigate the accordance of critical organscoring index (cosi), conformity index (ci) and normal tissue complicationprobability (ntcp) parameters with dose volume histograms (dvh) used forevaluation of 3 different pelvic radiotherapy plans. materials and methods:ten gynecologic carcinoma patients who underwent adjuvant radiotherapywere enrolled in this study. treatment plans were created with conformaltreatment planning (3dcrt) and intensity modulated radiation therapy(imrt) to a total dose of 50.4 gy in 28 fractions. initially, volume related doseevaluation was done via dvh. subsequently, hi, ci, cosi and ntcp forselected normal tissues were calculated for each plan and compared withdvh parameters. finally, a graphical demonstration was evaluated to see ifthe results were in accordance with dvh. results: ci results were statisticallysignificant in favor of imrt (p<0.001). rectum v40gy decreased with 9imrtcompared to 3dcrt and 7imrt (p=0.013 and p=0.013). v40gy for bladder wasalso lower with 9imrt compared with 3dcrt and 7imrt (p=0.005 andp=0.012). cosi calculations revealed better small intestine protection in imrtplans similar with dvh (p=0.005 and p=0.022). femoral heads were betterprotected with imrt plans were better compared to 3dcrt in ntcpcalculations (p=0.002). normal tissue protection was worst with 3dcrt viaboth dvh and cosi evaluations (p=0.001 and p<0.001 respectively).conclusion: using the indexes in this study to decide the most appropriateplan among multiple treatment plans in gynecologic cancer patients will betimesaving and easier in comparison with evaluating the dvh of everyalternative plan.