Abstract

In radiotherapy (RT), to determine the tumor volume (TV) and its morphology, computedtomography (CT) is used, acquiring images without and with intravenous iodinated contrastmedia (CM), where its influence has been poorly studied usually in artificial phantoms.Computerized dosimetries without and with CM from 10 CT of head and neck wereanalyzed using a before-after design. The same study group served as a control. Pointdoses and dose-area histogram (DAH) were evaluated, as well as a dose-volume histogram(DVH), using Student’s t-test with 5% significance. Before and after administering CM,the average difference between point doses was –0.09% within the confidence interval(CI) 0.27% and –0.45%, with a standard deviation (SD) 0.52%. The average doses usingDAH, resulted in a mean difference of 0.02%, within the 0.2% CI and -0.16%, with 0.27%SD. The standard volume within 100% of the dose utilizing DVH analysis resulted in anaverage of the differences of 0.1%, with CI 1.34% and –1.14% and SD 1.76%. The t-testof difference of means for paired designs, with α=0.05 found that there are no significantdifferences between the study and control groups for the different dose reading methods.