Dosimetric comparisons of dose calculation algorithms in prostate cancer treatment plans

2^nd World Congress on Cancer Science & Therapy

September 10-12, 2012 Hilton San Antonio Airport, USA

Suresh Rana

AcceptedAbstracts: JCST

Abstract :

Purpose/Objectives: RapidArc is a volumetric arc therapy technique that produces radiation dose distributions conformal to tumor while minimizing to surrounding critical structures. In order to achieve the best therapeutic advantage from RapidArc treatment for prostate cancer, media heterogeneities in photon beam path must be incorporated in dose calculation algorithm. The purpose of this study is to perform dosimetric comparisons between commercially available new Acuros XB Dose Calculation Algorithm (AXB) and widely tested Anisotropic Analytical Algorithm (AAA) in RapidArc prostate cancer plans. Methods: Ten patients with localized prostate cancer were selected. Planning target volume (PTV) and organs at risk (OARs) (rectum, bladder and femur heads) were contoured on CT dataset. Plans were created for 6 MV photon beam using RapidArc in Varian?s Eclipse treatment planning system. Dose calculations were performed with AXB and AAA for same number of monitor units and identical beam setup. Mean and Maximum doses to planning target volume and OARs were analyzed. Results: AAA predicted higher mean and maximum doses to PTV but dose difference was less than 1%. For OARs, mean and maximum doses in AAA plans were higher by in average 0.83% (range:0.23−0.99%) and 2.43% (range:2.31−2.62 %) respectively when compared against AXB plans. Significant differences (p<0.05) were observed for mean dose evaluations, whereas their statistical significance disappeared (p>0.05) for maximum dose data. Conclusion: The use of Acuros XB for dose calculation in RapidArc prostate cancer treatment plans shows dosimetric advantage over AAA with better sparing of OARs and lower mean and maximum doses to PTV.