Title: The application of contour-based optimization technique in the intensity-modulated radiation therapy for nasopharyngeal carcinoma
Abstract: Objective:To study the application of forward optimization technique in the intensity-modulated radiation therapy for nasopharyngeal carcinoma.Methods:From March 2003 to August 2010,92 patients with nasopharyngeal carcinoma underwent in-tensity-modulated radiation therapy and were considered in this retrospective study.All treatment plans were designed according to contour-based optimization technique based on the patient's anatomy,i.e.,on the outlined structures like planning target volume and organs at risk,or the apertures can be defined according to certain isodose-lines achieved with an open field.Results:The dose dis-tributions and dose-volume histograms met the demand of treatment in all patients.The doses of 95 percent(D95)of planning gross tumor volume of nasopharyn(PGTVnx)were greater than or equal to 70 Gy for all patients(92 /92).The D95s of planning target vol-ume of high risk region(PTV1)were greater than or equal to 60 Gy for 85 patients(85 /92),and the D95s of planning target volume of low risk region(PTV2)were greater than or equal to 54 Gy for 82 patients(82 /92).The maximum doses of cord were 45 Gy for all patients(92 /92).The mean number of segments was 39(range,29~65)and the median was 41.The mean total monitor units(MU)were 720.5(range,586.9~1 050.7)and the median was 758.6.The mean treatment time was 15.7 min(range,11.6~23.5 min)and the median was 16.5 min for 65 patients underwent after October 2006.Conclusion:This study suggests that intensity-mod-ulated radiation therapy appears to be a new effective option for nasopharyngeal carcinoma.The satisfactory dose distributions can be obtained using reasonable contour-based optimization technique.The superiorities of contour-based optimization such as deep de-creased segments can reduce total MU and shorten treatment,get more efficient treatment outcomes.
Publication Year: 2011
Publication Date: 2011-01-01
Language: en
Type: article
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