The Effect of Varying Collimator Angles on VMAT planning of Prostate Cancer

Background: The variation in collimator angles the Volumetric Modulated Arc Therapy (VMAT) has been a factor of consideration modern radiotherapy techniques for treatment cancer. Aim: To investigate dose-volume evaluation planning target volume (PTV) and organs-at-risk (OARs) prostate carcinoma patients planned with 1.5 arcs different angles. Methods: angle plays vital role VMAT due to leakage radiation from leaves multi-leaf (MLCs). Using same optimization parameters on designated system (TPS), plans were optimized 0°, 10°, 20°, 30°, 45°, 90°, 350°, 340°, 330°, 315° 270° Different like homogeneity index (HI), conformity (CI), gradient (GI), monitoring units (MUs), low dose coverage (V40Gy), maximum (Dmax), mean (Dmean), histogram (DVH), D98%, D95%, etc. calculated Anisotropic Analytical Algorithm (AAA) Version 15.6.04 results analyzed. Results: It was found that at 30° 45° angles, conformity, homogeneity, MUs have optimal values. organ risks all is not significantly affected by Conclusion: According this study it advised clinical medical physicists make solid decision about treatment. dosimetric analysis shows necessary plan analyzing better homogeneity. Keywords: Therapy. Prostate cancer, Planning Target Volume,