Dosimetric Influence of Acuros XB Dose-to-Medium and Dose-to-Water Reporting Modes on Carcinoma Cervix Using Intensity-Modulated Radiation Therapy and Volumetric RapidArc Technique

Aim: We aimed to evaluate the dosimetric influence of Acuros XB (AXB) dose-to-medium (Dm) and dose-to-water (Dw) reporting mode on carcinoma cervix using intensity-modulated radiation therapy (IMRT) and RapidArc (RA) technique. Materials and Methods: A cohort of thirty patients cared for carcinoma cervix was retrospectively selected for the study. Plans were computed using analytical anisotropic algorithm (AAA), AXB-Dm, and AXB-Dw algorithms for dosimetric comparison. A paired t-test and Pitman-Morgan dispersion test were executed to appraise the difference in mean values and the inter-patient variability of the differences. Results: The dose-volume parameters were higher for AXB-Dw in contrast to AAA for IMRT and RA plans, excluding D98%, minimum dose to planning target volume (PTV) and rectum mean dose (RA). There was no systematic trend observed in dose-volume parameters for PTV and organs at risk (OARs) between AXB-Dm and AXB-Dw for IMRT and RA plans. The dose-volume parameters for target were higher for AXB-Dm in comparison to AAA in IMRT and RA plans, except D98% and minimum dose to PTV. Analysis envisaged less inter-patient variability while switching from AAA to AXB-Dm in comparison to those switching from AAA to AXB-Dw. Conclusions: The present study reveals the important difference between AAA, AXB-Dm, and AXB-Dw computations for cervix carcinoma using IMRT and RA techniques. The inter-patient variability and systematic difference in dose-volume parameters computed using AAA, AXB-Dm, and AXB-Dw algorithms present the possible impact on the dose prescription to PTV and their relative constraints to OARs for IMRT and RA techniques. This may help in the decision-making in clinic while switching from AAA to AXB (Dm or Dw) algorithm for cervix carcinoma using IMRT and RA techniques.