Comparison of Volumetric Modulated Arc Therapy (VMAT) and Intensity Modulated Radiation Therapy (IMRT) Plannings for the Treatment of Left Sided Breast and Regional Lymphatic Tissue

摘要

Volumetric Modulated Arc Therapy (VMAT) technique can offer some distinct advantage over Intensity Modulated Radiation Therapy (IMRT) in limiting dose to the critical organs. In this study, our aim was to investigate the treatment plan quality and feasibility of a single isocenter VMAT plans for the treatment of left sided breast cancer including the whole breast, internal mammary nodes (IMN) and supraclavicular (S/C) nodes. For this purpose, ten left sided breast cancer patients were selected retrospectively who previously received radiation therapy using IMRT technique. A total of 4600 cGy for 23 fractions with 200 cGy per fraction was selected for the entire study and all the plans were done using VMAT and IMRT techniques. The plan quality of these two techniques was compared based on mean and critical organ volume receiving specific doses, conformity index, and equivalent uniform dose. The average mean dose to the heart was 5.00 ± 0.99 Gy for VMAT and 7.09 ± 1.70 for IMRT, and in the contralateral breast 2.83 ± 0.46 Gy for VMAT and 4.06 ± 0.61 for IMRT. Based on our study, single isocenter VMAT plan offers significantly lower dose to the heart and right breast over IMRT plans in treating the left breast and regional lymphatics using external radiation.