Optimization of three dimensional planning dosimetric in breast phantom for match region of supraclavicular and tangential fields

Aim: Complex geometry of breast tissue causes perturbation in dose distribution. This problem can beget overdose or under-dose points in match region of three fields. The aim of this study is to create dose homogeneity distribution in match region between tangential and supraclavicular fields (SCF) with Gafchromic external beam therapy (EBT) film. Materials and Methods: In this study, an anatomical slab phantom was designed with cork lung inhomogeneity and plexiy colored heart part. Conventional and three dimensional (3D) methods were utilized along with Gafchromic EBT film. Results: In asymmetric fields (3D method) much better results in match region were observed (i.e., maximum amount overlap area of 0.43 cm 2 , overlap depth of 3.55 cm and an average overlap width of 0.75 cm). Conclusion: This study revealed that EBT film is a proper tool for two dimensional (2D) relative-dose measurements. The study showed difficulties in achieving homogenous dose distribution in match region of tangential and supraclavicular.