Radiotherapy treatment plan quality metrics for breast cancer patients using conformal planning techniques

Abstract

Background: The purpose of this study is to evaluate and compare treatment plan quality metrics for postmastectomy breast cancer patients using 3Dimensional conformal radiotherapy (3DCRT) and intensity modulated radiotherapy (IMRT) planning techniques. Materials and Methods: The current study included 50 postmastectomy breast cancer patients out of which 24 were planned with 3DCRT and 26 with IMRT technique. Treatment plan quality metrics namely homogeneity index (HI), conformity index (CI), conformation number (CN), uniformity index (UI) and spillage index (R50), volume receiving 110% and 95% of prescribed dose (V110% and V95%) were calculated and compared for the two planning techniques. Results: IMRT plans have better conformity, homogeneity indices and low V110% than 3DCRT plans with almost similar R50% and V95%. Conclusions: Quantitative values of radiotherapy treatment plan quality metrics for the target are found in favour of IMRT technique than 3DCRT. Implementation of these five parameters is helpful for evaluating treatment plans along with slice by slice and DVH analysis. Keywords: Carcinoma of Breast; conformal planning techniques; radiotherapy.