Dosimetric study comparing intensity modulated and conformal pelvic radiotherapy boost plans in locally advanced cancer cervix

Purpose: This study was to compare 5 fields conformal technique to the intensity modulated radiotherapy (IMRT) 8 fieldstechnique in boosting locally advanced cancer cervix cases after external beam radiotherapy with respect to target volumecoverage and dose to normal tissues. Materials and methods: We conducted a single institutional comparative dosemetric analysis of 10 patients with cancercervix who was presented to radiotherapy department in National Cancer Institute, Cairo in period between June 2012 toSeptember 2012 and received a conformal radiotherapy (CRT) boost in the place of planned brachytherapy after large fieldpelvic radiotherapy (PRT) with concurrent chemotherapy were retrospectively identified. All tumors were situated in thelow central pelvis. Two plans were done for every patient; one using the 8 fields IMRT and the second one using 5 fields'3DCRTthe two techniques were then compared using dose volume histogram (DVH) analysis for the planning targetvolume (PTV), bladder, rectum and both femoral heads. Results: Comparing different DVHs, it was found that the PTV was adequately covered in both plans while it wasdemonstrates that the 8 fields IMRT technique carried less doses reaching organs at risk OARs (rectum, bladder, bothfemoral heads). Conclusions: From the present study, it is concluded that IMRT technique spared more efficiently OARs than CRTtechnique but both techniques covered the PTV adequately so whenever possible IMRT technique should be used.